• Title/Summary/Keyword: 중심 원리

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Comparison of Clinical Results of Excimer Laser Correction of Myopia and Compound Myopic Astigmatism Using VISX 20/20B $VisionKey^{TM}$ (VISX 20/20B $VisionKey^{TM}$ 엑시머레이저의 version 4.01 software를 이용한 근시교정술 및 근시성난시교정술의 임상성적 비교)

  • Lee, Sang-Bumm;Bae, Sang-Bok
    • Journal of Yeungnam Medical Science
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    • v.17 no.1
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    • pp.55-65
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    • 2000
  • Purpose: To compare the efficacy, predictability, stability and safety of excimer laser photorefracive keratectomy(PRK) for myopia and photoastigmatic refractive keratectomy(PARK) for compound myopic astigmatism. Methods: Two-hundred and three eyes(l18 eyes < -7D spherical equivalent, 85 eyes ${\geq}$ -7D spherical equivalent) received excimer laser correction for compound myopic astigmatism and 152 eyes(116 eyes < -7D, 36 eyes ${\geq}$ -7D) for simple myopia. A VISX 20/20B $VisionKey^{TM}$ excimer laser was used to perform either PARK or PRK. Visual acuity with and without correction, refraction, IOP, corneal haze, and topography were evaluated at 1, 3, 6, and 12 months postoperatively. All patients were followed up for more than 12 months. Results: Postoperative refraction were generally stable after 3 months without significant early overcorrection. At 12 months, 110(94.8%) eyes that underwent PRK and 104(88.1%) eyes that underwent PARK achieved UCVA of 20/30 or better in the group who had lower than -7D correction. For eyes treated with -7D or more, these figures were 31(86.1%) eyes after PRK and 57(67.1%) eyes after PARK. The incidences of within 1D of plano refraction at 1 year follow-up were 97.4% after PRK and 93.2% after PARK in the group who had lower than -7D correction. For eyes treated with -7D or more, these figures were 80.6% after PRK and 70.6% after PARK. Conclusions Myopia with or without astigmatism was successfully treated in most of the eyes using PRK or PARK with VISX 20/20B $VisionKey^{TM}$ excimer laser. The predictability and stability of the postoperative refraction during the first 12 months seem to be quite reliable. Further improvement of excimer laser system and software should increase the clinical outcomes and safety of refractive procedures.

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Compression Sensing Technique for Efficient Structural Health Monitoring - Focusing on Optimization of CAFB and Shaking Table Test Using Kobe Seismic Waveforms (효율적인 SHM을 위한 압축센싱 기술 - Kobe 지진파형을 이용한 CAFB의 최적화 및 지진응답실험 중심으로)

  • Heo, Gwang-Hee;Lee, Chin-Ok;Seo, Sang-Gu;Jeong, Yu-Seung;Jeon, Joon-Ryong
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.24 no.2
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    • pp.23-32
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    • 2020
  • The compression sensing technology, CAFB, was developed to obtain the raw signal of the target structure by compressing it into a signal of the intended frequency range. At this point, for compression sensing, the CAFB can be optimized for various reference signals depending on the desired frequency range of the target structure. In addition, optimized CAFB should be able to efficiently compress the effective structural answers of the target structure even in sudden/dangerous conditions such as earthquakes. In this paper, the targeted frequency range for efficient structural integrity monitoring of relatively flexible structures was set below 10Hz, and the optimization method of CAFB for this purpose and the seismic response performance of CAFB in seismic conditions were evaluated experimentally. To this end, in this paper, CAFB was first optimized using Kobe seismic waveform, and embedded it in its own wireless IDAQ system. In addition, seismic response tests were conducted on two span bridges using Kobe seismic waveform. Finally, using an IDAQ system with built-in CAFB, the seismic response of the two-span bridge was wirelessly obtained, and the compression signal obtained was cross-referenced with the raw signal. From the results of the experiment, the compression signal showed excellent response performance and data compression effects in relation to the raw signal, and CAFB was able to effectively compress and sensitize the effective structural response of the structure even in seismic situations. Finally, in this paper, the optimization method of CAFB was presented to suit the intended frequency range (less than 10Hz), and CAFB proved to be an economical and efficient data compression sensing technology for instrumentation-monitoring of seismic conditions.

Settling Characteristics of Natural Loess Particles in Seawater (해수 중에서 자연상태 황토입자의 침강특성)

  • KIM Sung-Jae
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.32 no.6
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    • pp.706-712
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    • 1999
  • PSD (particle size distribution) for 2,000 mg/$\ell$ natural loess in seawater showed normal distribution cure at 0 minute settling time, accompanying with very large particle distribution range with its mean particle diameter of 31.6 $\mu$m and coencient of variance of $72.6\%$, With elapsed time it showed that the PSD was rapidly changed from normal distribution cure to abnormal distribution curve, steepened the right-hand side of it and its coefficient of variance was getting increased because of rapid settling of large size particles, Cumulative weight distribution showed that 2,000 mg/$\ell$ natural loess in seawater was almost $100\%$ constituted of particles bigger than 20 $\mu$m in diameter. Ratio of $V_s/(D_{bm})^{1/2}$ for loess particles in seawater was increased with increase of particle size in geometrical progression. Almost all loess particles in seawater had Stokes settling velocity not less than 2,255 times of Brownian diffusion coefficient, There was almost to EDL (about 0.4 nm) around natural loess particles in seawater, Thus, there was always LVDW attractive force between loess particles approaching each other in seawater, and almost no EDL repulsive force. Loess particles were not always in the condition of easy floe formation. Concentration of natural loess in seawater increasing from 400 mg/$\ell$ to 10,000 mg/$\ell$, characteristics of the settling was changed from Type I settling (discrete settling) to Type II settling (flocculation settling). PVD (particle volume distribution) showed that natural loess particles in seawater were largely constituted of two types of particles, such as rapidly settling particles and suspended and dispersed particles for a long time. Amount of the latter was much less than that of the former.

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The Site Effect of the Broadband Seismic Stations in Korea (국내 광대역 지진 관측소의 부지효과)

  • Wee, Soung-Hoon;Kim, Sung-Kyun
    • Economic and Environmental Geology
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    • v.41 no.2
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    • pp.225-242
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    • 2008
  • The site effect for 23 broadband seismic stations in the southern Korean Peninsula was estimated by using the spectral ratio of coda waves. In principle, the site effect means the pure amplification below the station excluding effects of seismic source and attenuation in the wave transmission. However, the site effect determined in this study is equivalent with the relative site amplification factor to the mean amplification for all stations. A total of 500 three-component seismograms from 35 earthquakes, of which magnitude ranged from 2.5 to 5.1 occurred from January, 2001 to January, 2007 was used to obtain the site amplification factor. The site amplification factors were estimated for the frequency bands centered at 0.2, 0.5, 1, 2, 5, 10, 15, and 20 Hz. It was found that the factors for two horizontal components of transverse and radial records were concordant with each other in the all frequency bands. However, the factor for the vertical component was found to be systematically lower than those for two horizontal components. The factors obtained in the low frequency band below 2 Hz ranged from 0.5 to 1.5 in all seismic stations except for KMA and KIGAM stations in Bagryeongdo (BRD1 and BRD2) of which factor showed high value above 1.5. Some stations such as SEO, SNU, HKU, NPR, and GKPI showed high value above 1.5 in the high frequency band from 5 to 20 Hz. Especially, the factors of GKP1 station represented extremely high value ranging from 1.8 to 7.8. Also, the factors for stations of KWJ, SND, and ULJ showed low value below 0.5. The spatial distribution for the relative amplification factor represented a tendency of being approximately lower in north-eastern area than south-western area in the southern Korean Peninsula.

A study on optical coherence tomography system using optical fiber (광섬유를 이용한 광영상 단층촬영기에 관한연구)

  • 양승국;박양하;장원석;오상기;김현덕;김기문
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2004.04a
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    • pp.5-9
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    • 2004
  • In this paper, we studied the OCT(Optical Coherence Tomography) system which it has been extensively studied because of having some advantages such as high resolution cross-sectional images, low cost, and small size configuration. A basic principle of OCT system is Michelson interferometer. The characteristics of light source determine the resolution and the transmission depth. As a results, the light source have a commercial SLD with a central wavelength of 1,285 nm and FWHM(Full Width at Half Maximum) of 35.3 nm. The optical delay line part is necessary to equal of the optical path length with scattered light or reflected light from sample. In order to equal the optical path length, the stage which is attached to reference mirror is moved linearly by step motor And the interferometer is configured with the Michelson interferometer using single mod fiber, the scanner can be focused of the sample by using the reference arm. Also, the 2-dimensional cross-sectional images were measured with scanning the transverse direction of the sample by using step motor. After detecting the internal signal of lateral direction at a paint of sample, scanner is moved to obtain the cross-sectional image of 2-demensional by using step motor. Photodiode has been used which has high detection sensitivity, excellent noise characteristic, and dynamic range from 800 nm to 1,700 nm. It is detected mixed small signal between noise and interference signal with high frequency After filtering and amplifying this signal, only envelope curve of interference signal is detected. And then, cross-sectional image is shown through converting this signal into digitalized signal using A/D converter. The resolution of the OCT system is about 30$\mu\textrm{m}$ which corresponds to the theoretical resolution. Also, the cross-sectional image of ping-pong ball is measured. The OCT system is configured with Michelson interferometer which has a low contrast because of reducing the power of feedback interference light. Such a problem is overcomed by using the improved inteferometer. Also, in order to obtain the cross-sectional image within a short time, it is necessary to reduce the measurement time for improving the optical delay line.

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Analysis of the Contents of Clothing and Textiles Education of Practical Arts and Home Economics Education between before and after the Revision of the 7th Curriculum (2007 교육과정 개정 전과 후의 실과 및 가정과 의생활 교육내용 분석)

  • Park, Soon-Ja
    • Journal of Korean Home Economics Education Association
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    • v.19 no.3
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    • pp.37-60
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    • 2007
  • This study has been historically reviewed the clothing and textiles education through references. The clothing and textiles education had been informally offered as a part of household skill, skill of daily life and home skill before the law of school education was established. Therefore, we have reviewed the changes in the clothing and textiles education by separating the prior period between the end of the old Korea and the liberation in 1945, from the later period from the liberation up to now. And also contents of clothing and textiles education between before and after the revision of the 7th curriculum were compared and analyzed. The clothing and textiles education had put emphasis on sewing, handicraft and household during the prior period from the end of the old Korea to the liberation, but after liberation, it became involved in Home Economics Education. The number of classes and the contents of clothing and textiles education had been increased and deepened from the 1st term to the 5th term of curriculum. In particular, the 4th and 5th term of curriculum became a turning point where home life section was intensified. Even though the number of classes was reduced during the 6th term of curriculum, with increase in target school grades for this education, and Home Economics in the middle school remained an independent subject matter. However, during the 7th term of curriculum, Technology-Home Economics Education in the middle school courses led to losing independent subject name and shrinking its contents. Through the revision in the 7th curriculum, the clothing and textiles education achieved great improvement and progress by gaining balance in distribution of contents among school grades and balance between theory and practice. However it still remains as an issue to be more studied and resolved how well the contents are matched with the interests and attention of students. We need to consider and reflect request of students under learner-centered curriculum. Considering enormous changes in the environment surrounding the clothing and textiles education, it is crystal clear that the gap between existing contents of education and teaching methods and our real life will be widened. Because students' perceptions of value have been diversified, it is our task to develop better contents and learning system in order to help students have interests, attention and desire in clothing and textiles life in line with social needs for desirable clothing and textiles education.

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The Bibliographical Investigation of Sasang Constitution Diagnosis (사상체질(四象體質) 진단법(診斷法)의 문헌적(文獻的) 고찰(考察) - 외형(外形), 심성(心性), 증(證)을 위주(爲主)로 -)

  • Jung, Won-gyo;Kim, Jong-weon
    • Journal of Sasang Constitutional Medicine
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    • v.11 no.2
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    • pp.95-117
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    • 1999
  • 1. Purpose of study There are many Constitution theories. But, In the Sasang Constitutional medicine, the theory and the practice are connected systematically. So it has been used in Korea popularly. Lee Je-Ma suggested that the external form, the mind, the symptom are the criteria of Sasang constitution diagnosis at the Discourse on the Four Principle and the Discourse on the Identifying Four Constitutions. But The clinical importance study of three diagnostic criteria - the external form, the mind, the symptom - has never been studied. Therefore, there are many obstacles of using the three diagnostic criteria totally. And I think that it needs a study which we apply the three diagnostic criteria to practice and approve the clinical importance of one another. I classify and investigate the previous methods of Sasang constitution diagnosis by the three diagnostic criteria in this study. 2. Method of study I investigate the previous methods of Sasang constitution diagnosis bibliographically by Dongyi Soose Bowon, Journal of Constitutional medicine and other books. 3. Result of study (1) Study of the external form The Study of Ki-sang(氣像) and Sa-ki(詞氣) by experience and intuition was done previously, and study of imaginay formulation of each constitution by measuring Chae-hyung(體形) and yong-mo(容貌) has being done recently. (2) Study of the mind For the objectification of study and diagnosis, self-reporting questionnaire has been used. The ideal choice to determine an indivisual constitution, as far as questionnaire go, is to take results from both the modified version Sasang Pattern Identification Questionnaire and QSCCII. (3) Study of the symptom For the study of the symptom - constitution symptom and constitution symptom of disease - the study of principles, the clinical study of the type of disease and symptom, the study which the pathologic view of Oriental medicine apply the view of Sasang Constitutional medicine have been done. We must try to objectfy Sasang Constitutional disease.

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The Opening Space for Quality of Life in South Korea (삶의 질의 공간구조화 과정에 대한 사회학적 고찰)

  • 서문기
    • Korea journal of population studies
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    • v.20 no.2
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    • pp.181-198
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    • 1997
  • Going beyond the previous formulations of development theories, the present paper explores the effects other than political economy on quality of life in a rapidly developing country. The major analysis takes up the historical trend and nature of the developmental transformation that is partially a consequences of state structures and partially autonomous form it in South Korea. Also, it diagnoses developmental pathways for the future track by constructing a baseline model for state transition on the basis of power game between the state and civil society in the country. The results of the historical analysis show that civil society has been transformed in the course of confrontations and interactions between the state and nationalist social movement. The distinction between developmental(or bureaucratic authoritarian) and democratic state is presented to show that these are two qualitatively different aspects of state of state power, requiring separate analytical treatment. Furthermore, the state-centric approach which emphasizes the active role of the state at the sacrifice of societal fabric-constraining social conditions for quality of life - appears to be modified. On the contrary, the impact of civil society is transmitted both directly and indirectly via labor and ecological movement for quality of life, which is critical to the formation of the welfare state in the country. The prospect for sustainable development in Korea lies in providng and expanding quality of life in terms of the financial feasibility of the state through the public-private cooperation, and abstaining from drastic and radical commitment to welfare services as is the case with the European declines in welfare state, Further studies are needed to examine the interrelationships in different historical and cultural settings of developing counties to estimate a theory of quality of life and social justice.

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A Study of the Conservation Policy and Management Status of Historic Gardens in England - Focused on the National Trust - (영국 역사정원 보전정책과 관리현황에 대한 연구 - 내셔널 트러스트를 중심으로 -)

  • Yoon, Sang-Jun;Kwon, Jin-Wook
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.28 no.3
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    • pp.131-143
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    • 2010
  • This paper investigates the history, policy and status of the conservation of historic gardens in the National Trust in England and its implications for Korea. It was conducted in three phases as follows: First, related literature data was collected to understand the National Trust and its role in the conservation of historic gardens. Second, The National Trust Policy Papers: Gardens and Landscape Parks in 1996 was reviewed and analyzed into eight categories with a review of 216 gardens and interviews with gardener-in-charge via e-mail. Finally an understanding of the policy for the conservation of historic gardens was formed from the results of the previous phases, and implications were drawn from the integrated analysis guidelines of the policy and status. The key feature of the conservation of the National Trust's historic gardens is that the conservation process has been conducted systematically through acquisition, management, upkeep, advice and so on. Furthermore, the conservation principles are defined in a concise and accessible form. According to their practical conservation process and principles, the results of the National Trust activities are to appreciate the significance of the gardens and act with accountability; integration; managing change; access and participation; and training gardener and partnership. According to the results of its activities under the premise that the purpose of the conservation and the meaning of a garden do not differ significantly among nations, implications for Korea can be primarily suggested by three points as follows: First of all, a flexible approach to change in historic gardens should be managed. In response to inevitable and desirable change, anything that is added or transferred should be recorded for the future as much as possible. Therefore, everything must be recorded and any change should be managed. Second, is to provide sustainable access for the benefit for the people and visitors. The aim of conserving the gardens is for human's to eventually understand that the present generation just borrows the historic gardens before they are passed down. The ensuing implication is that people may enjoy the gardens educationally, aesthetically, and physically, and children can be continuously interested in historic gardens as apart of educating the future generation. Finally, the National Trust educates apprentice gardeners who will maintain the historic gardens and continuously keep the current garden staff up to date with workshops. This is in contrast to the day laborers who work for historic gardens in Korea. In practice, the maintenance of historic gardens is not a simple process. The gardener must understand the past, reflect the present, and prepare for the future. Therefore, gardeners deliver culture from generation to generation.

Study on the Origin of Stone Tower as a Component of Dangsan Forest - Focus on Village Shrine at Seoji-ri, Andong - (당산숲 구성요소인 돌탑의 기원 유래 고찰 - 안동 서지리 성황당 돌탑을 중심으로 -)

  • Choi, Jai-Ung;Kim, Dong-Yeob;Kwon, Jin-Ryang
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.28 no.3
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    • pp.98-104
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    • 2010
  • The objective of this study was to understand the origin and characteristics of stone tower's style through the study of the 'Village Shrine at Seoji-ri, Andong'. The three kinds of stone towers were located forming a line of 9m on the hill of a red pine forest along the stream in the village. Toward the direction looking at the village, the three-story stone located on left, the two-story stone located in the middle, and the common style stone tower located on right. The bottom part of the three-story stone was 2.5m in length, 1.8m in width, 1.3m in height. The bottom part of the two-story stone was 1.3m in length, 1.5m in width, 0.9m in height. The common style stone heap tower was 3.0m in diameter, 1.8m in height with a cone shape. The small hat-shaped stone was presumed to be the top part of a three-story stone. According to the three factors(heaven, earth, human) of the idea of the universe in Korea, most ancient remains have components of odd numbers. Then it had been substituted with smaller three-story stone(at present, two-story stone). And then altered to a common stone tower later, such as the 'Village Shrine at Seoji-ri, Andong' that shows the combination of the Bronze Age's megalithic and a folk religion. The 'Village Shrine at Seoji-ri, Andong' is a valuable relic that shows the stone towers, and is derived from the Bronze Age. The 'Village Shrine at Seoji-ri, Andong' shows that the 'Village Shrine at Seoji-ri, Andong' was embodied the three-factor(heaven, earth, human) idea of the universe in three-story stone of megalithic culture' remains.