• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.4
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• pp.515-523
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• 2012

In this paper, the resonance characteristics and radiation characteristics of a spherical patch on a dielectric sphere are analyzed. Resonance characteristics can be obtained from the resonant frequency and the quality factor. Radiation characteristics can be also analyzed from the E-field in the far region. In order to calculate these parameters, spectral domain analysis method is applied. Algebraic equation can be obtained in spectral domain through Vector Legendre transform pair and Galerkin's method. So, efficient calculation is possible numerically. It is investigated that radius, curvature of a spherical patch, and dielectric constant of a dielectric sphere have an effect on characteristics of a spherical patch.

• Proceedings of the Petrological Society of Korea Conference
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• 2002.05a
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• pp.1-38
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• 2002

옥천변성대 서남부지역은 변성이질암의 광물조합을 기준으로 남동부부터 북서방향으로 흑운모대, 석류석대, 십자석대의 3개의 변성광물분대로 나누어진다. Oh et al. (1995a)의 연구에서 보고된 남정석들은 산출되지 않는 것이 확인되었고 변성도는 흑운모대에서 석류석대를 거쳐 십자석대로 갈수록 증가한다. 쥬라기 화강암 접촉부의 국부적인 변성암류에서는 화강암에 의한 접촉변성작용에 의해 형성된 홍주석과 규선석이 산출된다. 흑운모대의 변성 압력-온도는 4.2 - 5.1 kb, 400 - 500 $^{\circ}C$이다. 십자석대의 정누대구조를 가지는 석류석과 석류석안의 사장석, 흑운모, 금흥석, 일메나이트포유광물의 공생관계로 추정한 압력-온도 (석류석 주변부: 7.0 - 8.0 kb, 550 - 620 $^{\circ}C$； 석류석 중심부: 4.0 - 5.0 kb, 420 - 520 $^{\circ}C$) 및 십자석대 내에서 후퇴변성작용 및 접촉변성작용 받은 석류석 주변부에 기록된 압력-온도 조건(약 2.0 - 3.0kb, 450 - 55$0^{\circ}C$)과 함께 옥천변성대 서남부지역의 변성암류가 시계방향의 압력-온도 경로를 겪었음을 지시한다. 연구지역 내에서 정밀 기재된 단면들에 대한 퇴적환경을 종합하면 대체 적으로 남동부에서는 천해성 환경이 인지되나 북서쪽으로 갈수록 대륙사면을 거쳐 분지 중심의 환경으로 전이되는 경향을 보인다. 이러한 퇴적상의 공간적 분포는 분지의 남동쪽보다 북서쪽의 침강이 우세하였던 것으로 해석될 수 있으며, 이는 곧 분지가 형성될 때 반지구대 (half graben) 형태로 분지가 열개 (rifting) 되었음을 의미한다. 각 변성분대에서 채취한 변성이질암으로부터 측정된 K-Ar 과 40Ar/39Ar 흑운모와 백운모 연대들은 149 - 167 Ma에 집중된다. 그리고 각 변성분대에서 동일시료에 대한 K-Ar 과 40Ar/39Ar 연대들은 동일시기를 지시함으로 연대적인 신뢰성을 확인 할 수 있었다. 옥천변성대 서남부지역의 변성암류를 관입하는 2개의 괴상의 화강암과 1개의 엽리화강암에서 얻어진 백운모와 흑운모들의 K-Ar 연대는 모두 156 Ma이며 옥천변성대 서남부지역의 변성이 질암의 연대와 유사하다. 이는 연구지역의 변성암류와 화강암류는 40Ar/39Ar 과 K-Ar 계의 흑운모와 백운모의 폐쇄온도 (약 300 - 350 $^{\circ}C$) 까지 동시에 냉각된 사실을 지시한다. 각섬석 편암내의 각섬석들은 복잡한 40Ar/39Ar 연대를 보여주며 일부가 평형연대를 보여주지만 특별한 의미 부여가 힘들다.

• Korean Journal of Optics and Photonics
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• v.23 no.3
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• pp.113-118
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• 2012

The concentration and hydrodynamic radius of nano-sized fluorescence particles diffusing in solution were compared by using fluorescence correlation spectroscopy (FCS), which can measure the variation of the correlation function of a fluorescence signal by size and number of particles. The used nano-sized fluorescence particles are Alex Fluor 647, quantum dots, and fluorescence beads, and three kinds of sample solutions with different concentrations were prepared by dilution to 1/10 and 1/100 with distilled water for each kind of particles. The effective focal volumes were calculated by using the known diffusion coefficient of Alexa Fluor 647 particles, and the diffusion time, number of particles in focal volume, and variation of concentration according to the dilution could be measured by the FCS system. Through this study, we determined that the concentrations of arbitrarily diluted sample solutions can be measured by a home-built FCS setup in the range of 0.1 nM ~ 10 nM and that the diffusion coefficient of the quantum dot was $27{\pm}1{\mu}m^2/s$.

• Journal of Satellite, Information and Communications
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• v.5 no.2
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• pp.34-39
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• 2010

Due to big demand for satellite and communication service using personal handheld terminals, demand for satellites with huge antennas is increasing correspondingly. While such large antennas are realized by various types of deployable antennas, the reflecting surface is made by many facets irrespective of deploying mechanisms. In order to analyze the faceted-reflector more accurately, an existing ray-tracing method is improved. The algorithm allows the rays to cross each other, which is the main characteristic of the faceted-reflector, and takes unevenness of amplitude and phase over the aperture plane into consideration. For the study of the effect of facet configuration, facet generating algorithm is devised. From the analysis algorithm and the facet-generating algorithm, it has been found that the number of facets in a radial direction affects both directivity and sidelobe level. On the other hand, the number of facets in a circumferential direction affects sidelobe level only.

• Journal of KIISE:Software and Applications
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• v.28 no.12
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• pp.938-946
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• 2001

A web support open environment in which flexibility that allows it to be applied in the education field has gradually evolved but the WBI(Web Based Instruction) which compose it have many limitations and problems, as far as learning efficiency is concerned. In particular, existing web-based estimation systems just give information on whether learner's replies are 'correct' or 'incorrect' and offer the learners evaluations of results in terms of scores. Therefore it is difficult for the learners to get more detailed information about their shortcomings and errors. What is needed for the learners is that web based instruction systems diagnose learner's comprehension status, providing c causes: Why did the learners make the errors\ulcorner In this paper, we propose the development of a web-based instruction system that learners can access with their browsers at any time and no matter where they are. Our system has a facility that analyses learner's weak points and diagnoses error cause, giving advice to learners and more detailed error information than existing systems. By accumulating user behaviors, relevant individualized information on the learners can be given.

• Journal of the Korean Institute of Intelligent Systems
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• v.20 no.6
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• pp.748-754
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• 2010

To reduce the computational cost required for assembling vessel fragments using surface geometry, this paper proposes a fast axis estimation method. Using circular constraint of pottery and local planar patch assumption, it finds the axis of the symmetry. First, the circular constraint on each cylinder is used. A circular symmetric pot can be thought of unions of many cylinders with different radii. It selects one arbitrary point on the pot fragment surface and searches a path where a circumference exists on that point. The variance of curvature will be calculated along the path and the path with the minimum variance will be selected. The symmetric axis will pass through the center of that circle. Second, the planar patch assumption and profile curve is used. The surface of fragment is divided into small patches and each patch is assumed as plane. The surface normal of each patch will intersects the axis in 3D space since each planar patch faces the center of the pot. A histogram method and minimization of the profile curve error are utilized to find the probability distribution of the axis location. Experimental results demonstrate the improvement in speed and robustness of the algorithms.

• Korean Journal of Environment and Ecology
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• v.27 no.5
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• pp.529-543
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• 2013

In this study, Pteridophytes flora of Jirisan National Park were recorded 135 taxa, and they belong to 21 families, 39 genera, 123 species, 11 varieties and 1 forma. In the field, 38 taxa were not found on literature exists and 22 taxa were newly confirmed. The results obtained from this study were as follows: Deciduous (d), Evergreen (e) and Summer-deciduous (sd) were calculated as 50.0%, 46.3%, 2.2%, respectively and the Deciduous (d) has the highest value compared to the other leaf phenologies. It observed from the life-form spectra that Hemicryptophytes (H) was the most common dormancy form at 44.8%. Geophytes (G), Epiphytes (E), Hydatophytes (HH), Therophytes (Th) and Chamaephytes (Ch) were calculated at 26.1%, 10.5%, 4.5%, 0.8% and 13.4%, respectively.

• Composites Research
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• v.26 no.2
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• pp.85-90
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• 2013

This paper presents the fabrication and 3-point flexion testing of carbon fiber reinforced polymer (CFRP) composite face/aluminum honeycomb core sandwich panels. Specimen sandwich panels were fabricated with three honeycomb types (3.18 mm, 4.76 mm, and 6.35 mm cell size) and three panel radii (flat, r = 1.6 m, r = 1.3 m). The curved sandwiches were fabricated normally with the core in the W-direction. The tensile mechanical properties of the CFRP $2{\times}2$ twill fabric face laminate were evaluated (modulus, strength, Poisson's ratio). The measured values are comparable to other CFRP fabric laminates. The flat sandwich 3-point flexion test core shear strength results were 11-30% lower than the manufacturer published data; the test set-up used may be the cause. With a limited sample size, the 1.3 meter panel curvature appeared to cause a 0.8-3.8% reduction in ultimate core shear strength compared to a flat panel.

• Journal of the Korean Institute of Intelligent Systems
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• v.19 no.6
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• pp.802-808
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• 2009

Recently many researches have been presented to improve the clustering performance of gene expression data by incorporating Gene Ontology into the process of clustering. In particular, Kustra et al. showed higher performance improvement by exploiting Biological Process Ontology compared to the typical expression-based clustering. This paper extends the work of Kustra et al. by performing extensive experiments on the way of incorporating GO structures. To this end, we used three ontological distance measures (Lin's, Resnik's, Jiang's) and three GO structures (BP, CC, MF) for the yeast expression data. From all test cases, We found that clustering performances were remarkably improved by incorporating GO; especially, Resnik's distance measure based on Biological Process Ontology was the best.

• Journal of Korean Society of Forest Science
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• v.3 no.1
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• pp.15-17
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• 1963

1) An experiment was made at the newly constructed glass house of Chun chan Agriculture callege to find out facts about the late-raising of Cortinellus edodes (Berk) Ido et Imai during the winter season. 2) The host timbers used in this experiment were Quercus Serrata Thumb and Quercus crispulo BI.; 5 years old each, the diameter ranging from 6cm to 17cm, dividing them into 12 diameter groups with 10 timbers in each group. The total number of timbess was 240 in two blocks. 3) As the pre-treatment of host timber, the autumn generation in 1962 was inhibited, and before being put into the glass-house, they were stimulated of generation for 3 days after 3 days, water-soaking. 4) The temperature control was made by using two coal stoves and the humidity control by spraying and two full water tanks. During cloudy weather and night, the green house was covered to preserue constant temperature of $5^{\circ}C{\sim}10^{\circ}C$. 5) The result; Quercus Serrata Thumb. with lesser diameter than 9cm showed no generation either in as big timber as one with diameter 11 cm. On the other hand, too big timbers showed low rate of generation; the reason, at a guess, is the too short period of cultivation and insufficient water soaking and inappropriate temperature. 6) The most standard size of host timber was found out be those with diameter 12cm~15cm in Quercus serrata Thumb, and those with diameter 14cm~17cm in Quercus crispula BI. Quercus crispula seemed to have slightly greater efficiency of generation than Quercus Serrata Thumb., but it could not be concluded as "decisive". Lastly, the host timber used in this experiment were old and the rate of generation was low as a whole.