• Restorative Dentistry and Endodontics
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• 제16권1호
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• pp.133-150
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• 1991

To study the mechanical behavior depended on the restoration method and alveolar bone height at endodontically treated teeth. a finite element model was made which was applied by four types of restoration methods and alveolar bone height on upper central incisor and then 1 Kg force was applied on each model as follows; 1) $45^{\circ}$ diagonal load on incisal edge. 2) $26^{\circ}$ diagonal load on lingual surface. and 3) horizontal load on labial surface. The author analyzed the displacement and stress of teeth and their supporting tissue by finite element method according to three type of loading conditions. The results were as follows : 1. The displacement by restoration method and the stress in dentin was found greater in restoration without a post than in that with a post. 2. The displacement and stress was found about the same when compared : A) in Resin model and PFM model applied by restoration method without a post and B) in PRC model and CPC model applied by restoration method with a post. 3. The lower alveolar bone height was. the greater was the displacement and stress. 4. The lower alveolar bone height was. the greater slightly was the stress of restoration without a post than in that with a post. 5. The stress in loading condition was the greatest in P1 in dentin and post. and was greatest in P3 in alveolar hone. 6. In the restoration method without a post. stress concentration in labial dentin was distributed to a figure of long belt in adjacent part to periodontal ligament. while in restoration method with a post. it was distributed in adjacent part to post side. And in all types of restoration method stress concentration in alveolar bone was distributed along the compact bone of labial and lingual surface.

• 한국환경복원기술학회지
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• 제3권1호
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• pp.20-26
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• 2000

In order to propose the design and installation information of vegetation belt, field investigation were carried out in the noise pollution control facilities of highway and the streets of a city for two years(1998~1999), and field tests were performed to analyze the noise attenuation effect of them. The noise pollution control facilities were generally classified into three types (noise barrier and vegetation belt type, mounding and vegetation belt type, vegetation belt type only). Most soundproof facilities were proved the noise reduction effects. But according to width, height, structure, auditory distance and planting forms of them, difference of noise reduction effects were investigated. The soundproof facility was suitable the mounding and vegetation belt type in the consideration of road environment, and the installation standard of vegetation was estimated that the width of vegetation was at least 20m and the length of that was 2 times in the distance from noise source.

• Archives of Plastic Surgery
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• 제41권6호
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• pp.734-739
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• 2014

Background Rupture is an important complication of breast implants. Before cohesive gel silicone implants, rupture rates of both saline and silicone breast implants were over 10%. Through an analysis of ruptured implants, we can determine the various factors related to ruptured implants. Methods We performed a retrospective review of 72 implants that were removed for implant rupture between 2005 and 2014 at a single institution. The following data were collected: type of implants (saline or silicone), duration of implantation, type of implant shell, degree of capsular contracture, associated symptoms, cause of rupture, diagnostic tools, and management. Results Forty-five Saline implants and 27 silicone implants were used. Rupture was diagnosed at a mean of 5.6 and 12 years after insertion of saline and silicone implants, respectively. There was no association between shell type and risk of rupture. Spontaneous was the most common reason for the rupture. Rupture management was implant change (39 case), microfat graft (2 case), removal only (14 case), and follow-up loss (17 case). Conclusions Saline implants have a shorter average duration of rupture, but diagnosis is easier and safer, leading to fewer complications. Previous-generation silicone implants required frequent follow-up observation, and it is recommended that they be changed to a cohesive gel implant before hidden rupture occurs.

• 한국환경복원기술학회지
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• 제7권1호
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• pp.10-18
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• 2004

The urban ecosystem, unlike the natural ecosystem, has been affected by the urban environment, so the existences of normal creatures have been threatened and eventually the stability has declined to consist of those that have adapted to such. Therefore, by creating a list of such organisms, their number of variety can be found out and their ecological distinction can be understood. Because flora is known to be an ecological index reflecting region's effects of human and societal environments, weather, and climates, it is a useful method of finding out the ecological position and distinctiveness of that region. The study site is part of watershed at Yangjae Stream, Kahngnam-ku, Seoul. In this study, the difference of flora in each land use type are investigated by plant identification. The purpose of this study is to evaluate the city's plant surviving environment, and eventually to contribute to the restoration of urban green spaces by finding out the plants which are appropriate for the corresponding environment. After doing the study, it was found that the urban forest is the most stable urban ecosystem while the urban park is seriously disturbed, and ecologically unstable. The urban stream is also disturbed continuously.

• 한국환경복원기술학회지
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• 제4권1호
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• pp.80-89
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• 2001

The objective of this study was to introduce the current status and development strategy for the environmental restoration of stream side in Japan, and to consider the methodology which could be effectively applied to the environmental restoration of stream side in Korea. 1. We should establish a new paradigm of forest conservation and erosion control which can emphasize the restoration of the stream side ecosystem and reduce soil movement in the areas. Also, in the past, the objective of forest conservation and erosion control was to fix soil by constructing permanent structures. The direction of future forest conservation and erosion control needs to be new forest conservation and erosion control technology to prevent large scale soil movement but allow small scale soil movement to conserve sound ecosystem and biotic habitats. 2. In the past, the goal of forest conservation and erosion control planning was to fix the amount of soil movement by constructing permanent facilities. Forest conservation and erosion control planning in the future needs to change the techniques which could prevent soil movement from large scale of soil disasters, but allow soil movement effectively to a small and middle scale's soil movement. Also, it is considered to change erosion control dams from non passing type to passing type. 3. In the point of ecological conservation aspects, we should evaluate the effects of new forest conservation and erosion control methods which are emphasized on the restoration of the stream side ecosystem. Also, forest conservation and erosion control construction projects for restoring stream and river ecosystem should be planned for perfectly restorating their ecosystems by the way of sustainable maintenance and management. 4. The restoration direction of stream and river ecosystems needs to be restoring the diversity of small geographies such as waterway, shoal and puddles rather than flattening stream bed. And the restoration of the stream side ecosystem should provide continuity of the stream side environment which allows desirable biological habitats, and environmentally sound facilities to harmonize with the environment.

• 한국환경복원기술학회지
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• 제19권1호
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• pp.185-193
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• 2016

Purpose of this study is to classify damaged lands according to the cause of the damage and their influences based on characteristic of the damaged lands in DeMilitarized Zone(DMZ) area, and utilize this study as a fundamental study for establishment of ecosystem restoration system. Literature review and field survey have been conducted to review the damage status of DMZ area. For field survey, first year and second year have been conducted, in which type of the damage has been reviewed in this study. In the result, types of damage have been classified into 6 categories: 'alteration of initial landform', 'loss of surface layer', 'land pollution', 'alteration of soil chemical property', 'decline of vegetation', and 'invasion of foreign species'. Restoration for each damage type is as following. First, for alteration of initial landform, the land is restored to the original landform prior to the damage and connection to surrounding ecosystem is considered. Second, for loss of surface layer, lost surface layer is restored or further loss is prevented with stabilization. Third, for land pollution, source of the pollution is eradicated or self-circulation with purification of polluted land is encouraged. Fourth, for alteration of soil chemical property, soil is restored of its original property with eradication of the pollution source and improvement of soil. Fifth, for decline of vegetation, current vegetation and anticipated alteration in future are considered and number of wild species is to be increased based on structure and characteristic of nearby vegetation. Sixth, for invasion of foreign species, prevention of dominance by risky species and facilitation ecological stability with ecological management are to be considered. Influence according to the cause of damage has occurred in secondary(indirect) influence or simultaneous occurrence of several damage types. Considering all these aspects, when type of the damage is complex, restoration process for each of former mentioned 6 damage types with solitary influence should be considered in unison.

• 한국환경복원기술학회지
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• 제25권5호
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• pp.43-57
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• 2022

This study aims to classify forest fire-affected areas, identify forest types by the intensity of forest fire damage using multi-time Landsat-satellite images before and after forest fires and to analyze the effects of artificial restoration sites and natural restoration sites. The difference in the values of the Normalized Burned Ratio(NBR) before and after forest fire damage not only maximized the identification of forest fire affected and unaffected areas, but also quantified the intensity of forest fire damage. The index was also used to confirm that the higher the intensity of forest fire damage in all forest fire-affected areas, the higher the proportion of coniferous forests, relatively. Monitoring was conducted after forest fires through Normalized Difference Vegetation Index(NDVI), an index suitable for the analysis of effects by restoration type and the NDVI values for artificial restoration sites were found to no longer be higher after recovering the average NDVI prior to the forest fire. On the other hand, the natural restoration site witnessed that the average NDVI value gradually became higher than before the forest fires. The study result confirms the natural resilience of forests and these results can serve as a basis for decision-making for future restoration plans for the forest fire affected areas. Further analysis with various conditions is required to improve accuracy and utilization for the policies, in particular, spatial analysis through forest maps as well as review through site checks before and immediately after forest fires. More precise analysis on the effects of restoration will be available based on a long term monitoring.

• 한국환경복원기술학회지
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• 제9권6호
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• pp.123-132
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• 2006

This research was studied to inverstigate the effect of plant mixtures and tackifibers on the vegetation of slope sites. 5 type plant mixtures(tree type, forest type, native herbaceous plant type, foreign herbaceous plant type, and cool-season turfgrass type) and 3 different tackifibers (Guar tackifibers, Polyarchrylamide tackifibers and Cellulose methyl starch) were treated with 3 replications on the experimented slope. The germination and coverage rate were high on native and foreign herbaceous plants and low on cool-season turfgrass, forest and tree types. We could notice that herbaceous plant types were effective on the vegetation of slope in the short term. Because tree or forest type vegetations similar to natural plant habitat, however, were preferable on slope vegetation in the long term, tree species of high germination rate should be selected in this experiment for tree or forest type slope vegetations. Tackifiber treatments increased the germination rate during the early treatment stage. However, the effect of tackifiber treatment on germination rate was decreased on the elapse of time. Guar tackifiber treatment was most effective on the vegetation of slope. As far as soil erosion control was concerned, all tackifiber treatments were effective compared to control.

• 헤리티지:역사와 과학
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• 제55권3호
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• pp.152-176
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• 2022

본고는 삼국시대 화살집 복원에 대한 기초 연구로, 기존 화살집 복원 안에 대한 세부내용을 보완하기 위한 연구이다. 현재 발굴된 삼국시대 화살집은 화살을 담는 주머니인 수납부, 그리고 화살집의 등판에 해당하는 배판부로 구성된다. 그러나 2부위는 남아있지 않고, 금속 부품만 발굴되고 있다. 출토된 화살집을 3가지 유형으로 분류하여 복원하였다. 수납부 금구를 중심으로 W자형 부품과 ㄷ자형 부품으로 구성된 1유형, 띠형 금구만 확인된 2유형으로 분류했다. 3유형은 2유형과 비슷하지만 적수금구에서 뻗친 철띠가 띠형 금구에 연결되는 화살집으로, 별도의 유형으로 상정하였다. 3가지 유형의 화살집에 대한 복원 안을 제시하기 전에 적수금구 위치와 유기물 관찰 내용을 반영하였다. 또 출토정황만으로 알 수 없는 적수금구의 위치와 같은 내용은 조선시대 화살집과 일본의 정창원, 하니와에서 관찰되는 화살집 착용방법에서 착안하였다. 적수금구를 기준으로 삼은 기존 화살집 변천 안을 참고하면, 화살집은 본고의 1유형에서 2·3유형으로의 변화한다. 변화의 요인에 대해 화살을 담는 수납부 공간과 화살집을 착용하는 방법의 변화에서 찾았다. 그러나 일부 2·3유형은 1유형의 착장 방식을 유지하고 있고 구식의 부품을 유지된 사례도 있었으며, 함안지역에서는 전형적인 1유형이 늦게까지 부장되는 양상을 확인할 수 있었다.

• Journal of information and communication convergence engineering
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• 제6권1호
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• pp.80-85
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• 2008

Images are often corrupted by noises during signal acquisition and transmission. Among those noises, additive white Gaussian noise (AWGN) and impulse noise are most representative. For different types of noise have different characters, how to remove them separately from degraded image is one of the most fundamental problems. Thus, a modified image restoration algorithm is proposed in this paper, which can not only remove impulse noise of random values, but also remove the AWGN selectively. The noise detection step is by calculating the intensity difference and the spatial distance between pixels in a mask. To divide two different noises, the method is based on three weighted parameters. And the weighted parameters in the filtering mask depend on spatial distances, positions of impulse noise and standard deviation of AWGN. We also use the peak signal-to-noise ratio (PSNR) to evaluate restoration performance, and simulation results demonstrate that the proposed method performs better than conventional median-type filters, in preserving edge details.