• The korean journal of orthodontics
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• v.27 no.5 s.64
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• pp.825-837
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• 1997

The purpose of this study was to evaluate the effect of splinting methods on the rearrangement of periodontal fibers after experimental tooth movement. Orthodontic force was applied by placing closed coil spring between upper third incisor and canine in seven dogs, weighing 20 kg or more. After 3 weeks of force application, 0.0215 inch multistrand wire and polyethylene ribbon were bonded to each side, as a flexible and rigid splinting respectively in 6 experimental animals. The remaining one served as a control. Each two animals were sacrificed at 4, 8 and 12 weeks after splinting respectively and prepared histologically for hematoxylin-eosin and Masson's trichrome staining. The results of this study were obtained as follows: 1. After tooth movement, periodontal space was narrowed and periodontal titers were thick on pressure side while elongated fibers were observed on tension side. 2. After 4 weeks of retention, the rearrangement of periodontal fibers was observed in the flexible splinting group, but not in the rigid splinting group. 3. After 8 weeks of retention, the rearrangement of periodontal titers was observed in both groups, but the difference could not be detected between two groups. 4. During the retention period, the rearrangement of periodontal fibers was faster in tension side than in pressure side. These results show that the rearrangement of periodontal fibers is also obtained by rigid splinting after tooth movement. It is suggested that the rigid splinting by polyethylene ribbon can be used as a way of postorthodontic retention.

• The Journal of the Acoustical Society of Korea
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• v.16 no.5
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• pp.76-82
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• 1997

The paper describes simulations and experimental results using a measuring system which utilizes the acoustic holographic method in order to exactly estimate an absolute position of a sound source. The measuring surface is installed to satisfy with a far field to the sound source and is composed of linear arrayed seven microphones. A measurement is simultaneously recorded by a reference microphone setting up a neighbour sound source and the linear arrayed seven microphones which are moved to the same interval. An absolute position of sound source is estimated by the cross-spectrum method to the received sounds between a reference and the measuring microphones. Phase differences of each microphone and time delays during scanning are compensated to the reference microphone and the measuring time of the first column. An optimal interval for each microphone in the measuring surface is decided by a numerical simulation. A source signal makes use of a sinusoid, and S/N ratio is 30dB in the experiment. The optimal microphone's interval in the simulation and the experiment is decided in order to satisfy with the Nyquist space sampling condition related to the wave length of 2kHz sinusoid. Mainlobe width of a estimated 3D hologram in the case of 2kHz source signal is decreased to 87% and 30% in comparison to 500Hz and 1kHz, and then a valid of simulation results is confirmed. Therefore, we verified a utilization of the study for a sound source estimation using 3ㅇ acoustic holographic method.

• Korean Journal of Environment and Ecology
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• v.5 no.1
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• pp.79-90
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• 1991

This study was conducted to investigate seasonal avifauna and to suggest a proper way how to manage and protect wild birds in Chirisan National Park. The survey was carried over 3 main trail districts by line transect method to figure out influence factor of inhabitation of wild birds from February to November in 1991. The study results are as follows : The observed birds were belong to 6 orders 24 families 49 species and 981 individuals and Falco tinnunculus(Natural monument No. 323). These birds also classified into 24 species for residents, 12 species for summer visitor. 9 species for winter visitor, 4 species for passage migrant, respectively. The observed average frequeney of birds was 2.09e.a./ha, and main dominant species were Parus varius, Parus major, Emberiza elegans, Garrolus glandarius, Sitta europaea, Hypsipetes amaurotis, Parus palustris in order. Cheoneun-sa trail route showed relatively decreasing trend of wild birds during spring and fall season because of the highest trail use of visitors. Maximum frequency of species and individuals appeared at Hwaum-sa route in spring and at Piagol route in fall. respectively. Those regions well explained the advantageous inhabitation area of birds in both regions. The diversity index of birds in winter showed little difference of similarity index due to balanced use of trails. Seasonal low similarity index in those 3 main trail district indicate a dissimilarity of environmental factors. Trail use restriction as a provision of proper management and protection of wild birds have to be made at Hwaum-sa route where propagation of birds actively occurred in spring and at Piagol route where birds wintering were observed will contribute to enhance species diversity in the future.

• The Korean Journal of Pain
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• v.1 no.2
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• pp.203-206
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• 1988

Evaluation of inadvertent dural puncture occuring among 308 epidural blocks done for the relief of pain from various conditions was performed. Dural puncture was suspected in 5 out of 308 epidural bloks. (1.6%) Aspiration of CSF was negative in 3 cases in which dural puncture was suspected only after developing spinal anesthesia. Of the 3 negative CSF aspirations, one case had a history of laminectomy. Adhesions of the adjacent tissues might result in the loss of flexibility and a decrease in potential epidural space which might cause dural tearing during injection and subarachoid injection of the local anesthetic followed by high spinal anesthesia. In another case, the needle tip was obstructed by tissue which led to negative aspiration of CSF and failure to feel loss of resistance. The second injection at the same site may cause subarachnoid injection of the local anesthetic through the previously perforated dura mater and in turn, lead to spinal anesthesia. In the last case, there was no reason to suspect dural puncture since the loss of resistance plus air rebound were definite and aspiration of CSF was negative, but dural puncture was suspected after the patient developed spinal anesthesia.

• Informatization Policy
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• v.28 no.3
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• pp.3-22
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• 2021

This article reviews previous literature on the metaverse and attempts to provide a refined definition for this phenomenon. Metaverse has recently been in the spotlight among discussions by the industry and the media while a consensus on the exact definition of metaverse is yet to be determined. Since Neal Stephenson first coined the term metaverse in his novel "Snow Crash" in 1992, the Acceleration Studies Foundation (ASF) was the first to analyze the concept of metaverse in 2007. While ASF's effort did not receive much spotlight it may have deserved, metaverse gained much attention in the fall of 2020 when NVIDIA announced its real-time simulation and collaboration platform for 3D production named "Omniverse" as a next-generation alternative for the Internet along with Roblox defining its service as metaverse during its IPO. Since then, metaverse has been commonly recognized as a world where we can cross over reality and virtuality. Based on the two axes and four scenarios proposed by the ASF, we review the literature across four realms as follows - virtual reality, mirror world, augmented reality, and lifelogging. Then, we examine the issues with the existing definition of metaverse and propose an alternative explanation by focusing on human behavior and user experience. Finally, we reassess the concept of metaverse and incorporate human communication, reality-based and virtual-based activities, and eXtended reality as elements to properly define metaverse.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.32 no.3
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• pp.45-65
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• 2021

How are real libraries affected and what are they planning and working on in the current coronavirus era? Based on these questions, the purpose of this study was to analyze the Corona-related trends based on the 2020 implementation plan of the Library Development Comprehensive Plan and the 2021 implementation plan, and to analyze the impact and changes of the libraries in the city and the direction of corona response. The problems in the 2020 municipal libraries are largely attributed to the closure or curtailment of libraries due to the epidemic of coronavirus, budget cuts and budget limits due to coronavirus, declining users' interest and participation, infrastructure limits due to rapid service changes and operational limitations. Furthermore, the improvement measures and future plans could be divided into 1) development and provision of non-face-to-face programs; 2) development and provision of online-based services; 4) expansion of budget for response to demand; 5) provision of space against corona; and other response directions. In addition, in order to systematically cope with coronavirus in the future, it is expected that first, hybrid-type programs and services, second, infrastructure for online and non-face-to-face services, and third, budget utilization flexibility will be required.

• Applied Microscopy
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• v.29 no.1
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• pp.25-41
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• 1999

The experiment was performed to study the morphological responses of the renal glomeruli of the mice after administration of 5-fluorouracil or mitomycin C. 5-fluorouracil (60 mg/kg) or mitomycin-C $(400{\mu}g/kg)$ were injected subcutaneously to the animals every other day, and animals were sacrificed at 4 days or 7 days following the first injections. Pieces of tissues were observed with a JEM 100CX-II electron microscope. The observed results were as follows: 1. In the fourth day following the first injection of 5-fluorouracil or mitomycin C, components of the renal glomeruli of the mice are looked compact since they were filled with the widened the mesangium, and showed narrowing lumen of glomerular capillaries and of urinary spaces. The changes were more significant in the mitomycin C treated mice. 2. In the 5-fluorouracil treated mice, morphological changes of glomeruli were generally recovered in the seventh day, whereas the glomeruli of the mitomycin C treated mice have not shown general recovery. 3. In the fourth and seventh days following the first injection of mitomycin C, in the renal glomeruli of the mice, swollen endothelial cells, and protruded mesangeal cells into the capillary lumen are frequently observed. 4. In the fourth day following the first injection of mitomycin C, in the glomerular basal lamina of the mice, the electron densities of the lamina rara interna and the lamina rara externa were similar to the density of the lamina densa and the expanded lamina rara interna were often seen. From the above results, it is suggested that the cytotoxic effects of the mitomycin C on renal glomeruli are more severe as compared with those of 5-fluorouracil.

• Journal of Internet of Things and Convergence
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• v.9 no.2
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• pp.19-31
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• 2023

The importance of barrier free is being highlighted worldwide. This study attempted to identify barrier-free research trends using text mining. Through this, it was intended to help with research and policies to create a barrier free environment. The analysis data is 227 papers published in domestic academic journals from 1996 when barrier free research began to 2022. The researcher converted the title, keywords, and abstract of an academic thesis into text, and then analyzed the pattern of the thesis and the meaning of the data. The summary of the research results is as follows. First, barrier-free research began to increase after 2009, with an annual average of 17.1 papers being published. This is related to the implementation guidelines for the barrier-free certification system that took effect on July 15, 2008. Second, results of barrier-free text mining i) As a result of word frequency analysis of top keywords, important keywords such as barrier free, disabled, design, universal design, access, elderly, certification, improvement, evaluation, and space, facility, and environment were searched. ii) As a result of TD-IDF analysis, the main keywords were universal design, design, certification, house, access, elderly, installation, disabled, park, evaluation, architecture, and space. iii) As a result of N-Ggam analysis, barrier free+certification, barrier free+design, barrier free+barrier free, elderly+disabled, disabled+elderly, disabled+convenience facilities, the disabled+the elderly, society+the elderly, convenience facilities+installation, certification+evaluation index, physical+environment, life+quality, etc. appeared in a related language. Third, as a result of the CONCOR analysis, cluster 1 was barrier-free issues and challenges, cluster 2 was universal design and space utilization, cluster 3 was Improving Accessibility for the Disabled, and cluster 4 was barrier free certification and evaluation. Based on the analysis results, this study presented policy implications for vitalizing barrier-free research and establishing a desirable barrier free environment.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.94-98
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• 2006

미계측 유역에 대한 정확한 수문반응을 예측하기 위해 수문반응 모의할 때 발생하는 불확실성을 예측하고 감소시킬 필요가 있다. 이러한 불확실성은 사용가능한 자료의 질과 양에 따라 달라지므로, 자료의 해상도는 수문반응 예측에서 중요한 요소가 된다. 그러므로 본 연구에서는 격자크기가 수문모형의 강우-유출응답모의에 어떠한 영향을 미치는지 살펴보았다. 격자크기가 입력데이터의 정보 손실을 발생시키지 않는 경우의 모형의 불확실성을 조사하기 위하여, 2차 및 3차 하천차수와 유역면적의 증가를 고려한 4가지 가상유역을 구성 하였다. 50m, 100m, 250m, 500m, 1000m의 격자를 사용하여 강우-유출모의를 수행하고, 격자에 따른 모의결과를 비교하기 위해 유출구의 수문곡선을 작성하였다. 또한, 소유역에서 하천으로 유입되는 단위길이당 유량과 하천의 합류점 전..후 및 유출구의 하천유량에 대한 Nash 계수를 산정하고 비교하였다. 기준이 된 격자크기와의 차가 큰 격자가 사용된 경우 모의된 수문반응의 차이는 증가하였고, 대상 유역의 면적이 커질수록, 하천차수가 작을수록 그 차이는 감소하였다. 소유역에서 하천으로 유입되는 단위폭당 유량의 오차는 흐름길이가 증가할수록 감소하였다. 흐름길이가 일정한 소유역으로만 구성된 가상유역 I, II에 대한 수문모의에서 하천유량의 오차는 하천을 따라 증가한 반면, 각기 다른 흐름길이의 소유역으로 구성된 가상유역 III, IV의 경우, 오차는 하천의 흐름에 따라 일정한 경향을 갖지 않고, 하천의 합류를 통해 증가되거나 감소하였다. 이 경우, 유역 유출구의 총체적 수문반응의 오차는 1차 하천의 합류후 발생한 최대오차보다 작았다.량을 산출하여 하천환경정비를 위한 기초자료로서 활용 될 수 있도록 하였다.구에 맞는 작물 생산 및 농촌관광단지 조성을 통해 부가가치증대 및 소득증대를 꾀함으로 농촌문제 해결에 도움이 될 것으로 기대된다. 본 연구를 통해 GIS 와 RS의 기술이 농촌분야에 더 효율적으로 적용될 것으로 기대되며, 농업기술센터를 통한 정보제공을 함으로써 대농민 서비스 및 농업기관의 위상이 제고 될 것으로 기대된다.여 전자파의 공간적인 가시화를 수행할 수 있었다. 본 전자파 시뮬레이션 기법이 실무에 이용될 경우, 일반인이 전자파의 분포에 대한 전문지식을 습득할 필요 없이, 검색하고자 하는 지역과 송전선, 전철 등 각종 전자파의 발생 공간 객체를 선택하여 실생활과 관련된 전자파 정보에 예측할 수 있어, 대민 환경정보 서비스 질의 개선측면에서 획기적인 계기를 마련할 것으로 사료된다.acid$(C_{18:3})$가 대부분을 차지하였다. 야생 돌복숭아 과육 중의 지방산 조성은 포화지방산이 16.74%, 단불포화지방산 17.51% 및 다불포화지방산이 65.73%의 함유 비율을 보였는데, 이 중 다불포화지방산인 n-6계 linoleic acid$(C_{18:2})$와 n-3계 linolenic acid$(C_{18:3})$가 지질 구성 총 지방산의 대부분을 차지하는 함유 비율을 나타내었다.했다. 하강하는 약 4일간의 기상변화가 자발성 기흉 발생에 영향을 미친다고 추론할 수 있었다. 향후 본 연구에서 추론된 기상변화와 기흉 발생과의 인과관계를 확인하고 좀 더 구체화하기 위한 연구가 필요할 것이다.게 이루어질 수 있을 것으로 기대된다.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.66-71
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• 2006

최근에 하도계획의 주된 과제는 하천환경의 보전과 창조를 위한 비용의 최소화이며, 침식과 세굴에 대한 하천관리 시설의 안정성을 확보하기 위한 질적 안전도의 최대화에 있다. 이를 위해 하도의 변화를 전제로 이동상 현상을 고려하고 저수로의 특성을 파악하여 하도계획에 반영하는 것이 필요하다. 이러한 하도계획과 관리를 위한 주요한 도구로서 하도특성조사가 제시되고 있다. 우리나라에서는 수변 생태환경의 기능회복으로의 하천환경에 관심을 기울이기 시작한 단계에 머물러 있다. 국내에서도 일본 등 선진 외국과 같이 홍수시 재해를 크게 경감하고, 자연환경을 실질적이고 체계적으로 배려하면서 경제적 하도계획 및 관리에 역점을 두어야 할 시점에 이르렀다. 이를 위해서는 우선적으로 하천이 갖고 있는 고유 특성인 하도특성에 대한 조사가 선행되어야 한다. 본 연구에서는 대상하천을 선정하고 측량, 하상재료 채취 및 분석, 유사량 채취 등의 기초조사를 수행하였으며, 이에 따른 하도특성량을 분석하였다. 대상하천은 금강유역의 지천 하류부의 약 2km 구간을 선정하였으며, 2003년${\sim}$2004년에 3회에 걸쳐 측량을 실시하고, 구간내 구룡수위표에서 유량 몇 유사량을 측정하였다. 또한 대상구간내 14개 지점에서 하상토를 채취하여 입도분석을 실시하였으며, 구룡수위표 자료를 이용하여 수문자료를 구축하였다. 수집된 기초자료를 이용하여 대상구간의 강턱유량, 특정재현기간유량, 유효유량을 산정하여 지배유량을 결정하였다. 산정된 지배유량을 이용하여 하상경사, 대표입경, 저수로내 평균수심, 에너지 경사, 마찰속도, 무차원소류력, 하폭-수심비, 수심-입경비 등의 하도특성량을 산출하여 하천환경정비를 위한 기초자료로서 활용 될 수 있도록 하였다.구에 맞는 작물 생산 및 농촌관광단지 조성을 통해 부가가치증대 및 소득증대를 꾀함으로 농촌문제 해결에 도움이 될 것으로 기대된다. 본 연구를 통해 GIS 와 RS의 기술이 농촌분야에 더 효율적으로 적용될 것으로 기대되며, 농업기술센터를 통한 정보제공을 함으로써 대농민 서비스 및 농업기관의 위상이 제고 될 것으로 기대된다.여 전자파의 공간적인 가시화를 수행할 수 있었다. 본 전자파 시뮬레이션 기법이 실무에 이용될 경우, 일반인이 전자파의 분포에 대한 전문지식을 습득할 필요 없이, 검색하고자 하는 지역과 송전선, 전철 등 각종 전자파의 발생 공간 객체를 선택하여 실생활과 관련된 전자파 정보에 예측할 수 있어, 대민 환경정보 서비스 질의 개선측면에서 획기적인 계기를 마련할 것으로 사료된다.acid$(C_{18:3})$가 대부분을 차지하였다. 야생 돌복숭아 과육 중의 지방산 조성은 포화지방산이 16.74%, 단불포화지방산 17.51% 및 다불포화지방산이 65.73%의 함유 비율을 보였는데, 이 중 다불포화지방산인 n-6계 linoleic acid$(C_{18:2})$와 n-3계 linolenic acid$(C_{18:3})$가 지질 구성 총 지방산의 대부분을 차지하는 함유 비율을 나타내었다.했다. 하강하는 약 4일간의 기상변화가 자발성 기흉 발생에 영향을 미친다고 추론할 수 있었다. 향후 본 연구에서 추론된 기상변화와 기흉 발생과의 인과관계를 확인하고 좀 더 구체화하기 위한 연구가 필요할 것이다.게 이루어질 수 있을 것으로 기대된다.는 초과수익률이 상승하지만, 이후로는 감소하므로, 반전거래전략을 활용하는 경우 주식투자기간은 24개월이하의 중단기가 적합함을 발견하였다. 이상의 행