• Journal of the Korean Institute of Landscape Architecture
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• v.14 no.2
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• pp.27-42
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• 1986

The vegetation structure in the Hoo - Won, Changduk Palace in Seoul was analysed on 10 sites sampled for understanding structure of natural vegetation. The main vegetational survey was conducted during July, 1985 and actual vegetaion and degree of natural vegetaion types were surveyed additionally. The result summarized of this research are as follows. 1) The physical - chemical conditions of soil showed middle class. This might be derived by short succession period from Pine forest to decidious broadleaf forest and artificial impact by human intervention. 2) When considering dominance species by crown story, Quercus aliena was a dominant species over all site and Castanea crenata, Prunus sargentii and Quercus variabilis appeared as a dominant species locally at upper story. Styrax story and Rhododendron mucronulatum, Styrax japonica, Stephanandra incisa and Lespedeza spp. at lower story. 3) The distances kept by trees per crown story are as follows. The mean distances between trees were 4.5-5.5m at upper story, 2.8-3.3m at middle story. On the other hand, the mean distances between dominant species were 6-8m at upper story, 5-9m at middle story. 4) The vegetation in this area was not developed yet into dominant species community according to the similarity analysis. The natural vegetation was dominated by Quercus spp. especially Quercus aliena according to the analysis of species diversity, relative dominance by story and DBH class. On the orther hand, succession to climax stage dominated by shade tolerent species will take a long time due to little appearance of shade tolerence species by previous heavy artificial impacts on understory species. 5) Quercus forest took possesion of 71.3%(27.37ha) of total forest area when considering the actual vegetation and especially Quercus aliena community covered 53.2%(15.21ha). Carpinus laxiflora community, one of the climax species in temperate zone, took possesion of 1.0%(0.3ha) and Pine densiflora was almost disappeared due to species competition. 6) According to the degree of natural vegetation types, the possession of degree of 6-9 was 60.6% and degree of 7-8, substitute vegetation, was 15.5%. The possesion of degree of 9 which consists of over 50 years old trees simliar to natural vegetaion was the highest, 43.1% in this area. Therefore continuous protection in this area of degree of 9 should be recommended.

• The Journal of Korean Academy of Prosthodontics
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• v.37 no.1
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• pp.104-126
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• 1999

The purpose of this study was to compare and evaluate the stress distribution and displacement developed in the abutment teeth and residual ridge area by madibular unilateral distal extension removable partial denture with 2 different retainer designs. The retainers on right and left canine and right 2nd molar were Alters clasp in one model and telescopic crown in the other model. The stress distribution of abutment teeth and residual ridge area on two model were compared and analyzed with 3-dimensional finite element method. 150N and 400N forces were applied vertically, 30 degree and horizontally on the central fossa area of left 1st molar of the removable partial denture, and then stress distribution patterns were analyzed and compared. The results were as follows 1. As the magnitude and angulation of applied force were increased, the magnitude of stress on the right and central residual ridge area and the right canine of the telescopic type increased and comparing to those of the Alters clasp type. 2. As the magnitude and angulation of applied force were increased, the mesial direction of displacement on the right residual ridge area and the right tooth of the telescopic type increased and the distal direction of displacement on left residual ridge area and the left canine increased comparing to those of Akers clasp type. 3. As the vertical force was applied, the distal direction of the displacement of the right tooth were greater and that of the left canine was smaller and the upward displacement of the right canine was greater in telescopic partial denture than those of Akers clasp type. 4. As the 30 degree force was applied, the mesial direction of the displacement of the right tooth were greater and the distal direction of the displacement of the left canine was smaller and the upward displacement of the right canine was greater in telescopic partial denture than those of Akers clasp type. In the horizontal force the results were same in right area tooth but the distal direction of displacement was greater in left canine. 5. In both removable partial dentures, as the magnitude and degree of force were increased, the stress and displacement were increased. The compressive force was dominative than the ten sile force. 6. In both removable partial dentures, the magnitude of stress was greater on mucosal tissue area than that of the alveolar bone area on distal extension residual ridge area but the result was reversed on anterior residual ridge area. The displacement was always greater on mucosal tissue area than that of alveolar bone area.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.30 no.1
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• pp.60-71
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• 2008

The objective of this study is to evaluate the stress distribution according to the thread design and the marginal bone loss of a single unit dental implant under the axial and offset-axial loading by three dimensional finite element analysis. The implants used had the diameter of 5mm and 4mm with 13mm in length and prosthesis with a conical type which is 6mm in height and 12mm in diameter. The thread designs were triangular, square and buttress. In the three dimensional finite element model with $15\times15\times20mm$ hexahedron and 2mm cortical thickness, implants were placed with crown to root ratio 7:12, 10:9, 13:6 and 16:3. And additionally the axial force of 100N were applied into 0mm, 2mm and 4mm away from the center of the implants. The results were as follows 1. The maximum von-Mises stress in cortical bone was concentrated to cervical area of implant, and in cancellous bone, apical portion. 2. Comparing the von-Mises stresses in cortical bone of 2mm and 4mm offset loading with central axial loading, it were increased to 3 and 5 times in diameter 4mm implant, and 2 and 4 times, in diameter 5mm implant. 3. The square threads were more effective than the triangular and butress as the longer diameter, the offset loading, and the worse crown to root ratio. 4. The von-Mises stresses were relatively stable until crown to root ratio 13:6, but it was suddenly increased at 16:3. From the results of this study, minimum requirement of crown to root ratio of implant is 2:1, and in the respect of crown to root ratio, diameter and offset loading, square threads are more effective than triangular and buttress threads.

• Korean Journal of Medicinal Crop Science
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• v.5 no.3
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• pp.237-242
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• 1997

The experiment was conducted to find causes of rooting failure in divided crown of peony cultivation. The results were as follows : In farmer s fields, damage rate of rooting failure in divided crown of peony was 32% as non-sprouting 5.6%, withering after sprouting 20.7%, and wilting after sprouting 5.7%, repectively. Damage degree in farmer s fields was followed, above 70% by 4%, 41 to 70% by 17%, 11 to 40% by 45% per total field area, respectively. It was caused by rooting failure. Damage rate of rooting failure as affected by different planting time was 18.2% for planting in autumn, 42.9% for planting in spring, and damage in divided crown was higher than in seedling. As periods to planting were prolonged, growth and yield were larger poorly, treatment with seminal-root sterilization and soil insecticide showed good growth and rooting but untreated control was very poor. Main cause of rooting failure in divided crown of peony was disease, Cylindrocarpon sp. and low quality of seeds.

• Proceedings of the KACD Conference
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• 2001.05a
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• pp.247-251
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• 2001

;A dental developmental anomaly is defined as an isolated aberration in tooth form, caused by a disturbance or abnormality which occurred during tooth development. There are numerous types of dental anomalies, and a considerable variation in the extent of the defects occurs with each type. Teeth with these anomalies pose unique challenges. Since the defects are not always apparent clinically, they can confuse diagnosticians investigating the etiology of pulpal pathosis. When endodontic treatment is required, the defects often hinder access cavity preparation and canal instrumentation. Treatment planning also becomes more challenging, since the defects can create complicated periodontal problems, and the malformed teeth can be difficult to restore, particularly those weakened by endodontic therapy. Fusion is defined as the joining of two developing tooth germs resulting in a single large tooth structure. The incidence of fusion is < 1% in the Caucasian population, and it is believed that physical force or pressure produces contact of the developing teeth. Clinically and radiographically, a fused tooth usually appears as one large crown with at least partially separated roots and root canals. There may be a vertical groove in the tooth crown delineating the originally separate crowns. Dens invaginatus is a deep surface invagination of the crown or root that is lined by enamel. Teeth in both maxillary and mandibular arches may be affected, but the permanent maxillary lateral incisor is the tooth most commonly involved. Studies have revealed an incidence ranging from 0.25% to as high as 10%. The invagination ranges from a slight pitting to an anomaly occupying most of the crown and root. The invagination frequently communicates with the oral cavity, allowing the entry of irritants and microorganism either directly into pulpal tissues or into an area that is deparated from pulpal tissues by only a thin layer of enamel and dentin. This continuous ingress of irritants and the subsequent inflammation usually lead to necrosis of the adjacent pulp tissue and then to periapical or periodontal abscesses. If the invagination extends from the crown to the periradicular tissue and has no communication with the root canal system, the pulp may remain vital. Recommended treatment of fused tooth and dens invaginatus has been reported in the endodontic literature. This case report describes the endodontic treatment of a maxillary laterl incisors having fused crown and dens invaginatus.natus.

• Journal of Korean Society of Forest Science
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• v.100 no.1
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• pp.8-13
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• 2011

This study was carried out to investigate the change of photosynthesis, leaf and fruit according to crown layers in Actinidia arguta and hybrid kiwi. Photosynthesis rate (PPFD $1,000{\mu}mol{\cdot}m^{-2}s^{-1}$) were 5.82, 7.11, $9.54{\mu}mol\;CO_2\;m^{-2}s^{-1}$ at lower, middle, and upper position, respectively in 3 layer cultivation type. The length and area of leaves collected from lower position have lager value than upper position. The fruit quality of A. arguta and hybrid kiwifruit increased with increasing crown height. A linear correlation ($R^2=0.72$, 0.89 and 0.98) was shown between fruit weight (Boeun 4, Injea 16 and HM3) and the height of crown layer(layer 1, 2, and 3). From the results, we can suppose that the tree of the upper position of crown layer in the cultivation of A. arguta and hybrid kiwifruit produce high quality fruit due to its high photosynthesis ability.

• Korean Journal of Remote Sensing
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• v.28 no.5
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• pp.587-596
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• 2012

Verifying about eligibility of targeted site is necessary for execute Afforestation and Reforestation Clean Development Mechanism (A/R CDM) project which is followed by system of Kyoto protocol. The site have to be identified by which could not be in conformity with definition of forest. This study tried to propose a technology of classify for site selection of A/R CDM. We chose several parts of Yangpyeng as study area and applied LiDAR data and remotely sensed imagery for considering about tree height, degree of crown closure, and land area which 3 factors for identify forest. LiDAR data was used for offset the shortage of remotely sensed imagery that cannot perfectly determine the forest definition due to absence of 3-dimentional information, but can be obtained from LiDAR. Considering tree height, degree of crown closure, and land area simultaneously by moving window, classified fields to forest and non forest based on pixel size. As a result, 124.06 ha for suitable to doing plantation and approximately 357.02 ha are in negative. Technology that applied for analyzing will provide fundamental methodology not only site selection for A/R CDM, but will be utilized in other Kyoto protocol.

• Journal of Dental Rehabilitation and Applied Science
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• v.22 no.4
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• pp.329-340
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• 2006

Statement of problem: Damping of the peak force transmitted to implants has been reported by in vitro studies using impact forces on resin-veneered superstructures. Theoretical assumptions suggest that use of acrylic resin for the occlusal surfaces of a prosthesis would protect the connection between implant and bone. Therefore, the relationship between prosthesis materials and the force transmitted through the implant system also needs to be investigated under conditions that resemble the intraoral mechanical environment. Purpose: The purpose of this study was to analyze the fracture strength and modes of temporary prosthesis when a flange or occlusally extended structure were connected on the top of the abutment. Material and method: Modified abutments of winged and bulk design were made by casting the desired wax pattern which is made on the UCLA type plastic cylinder. Temporary crowns were made using templates on the modified abutments, and its fracture toughness and strain were compared to the traditional temporary prosthesis. To evaluate the effect of aging, 5.000 times of thermocycling were performed, and their result was compared to the 24hours specimen result. Results: The following conclusions were drawn from this study: 1. In the fracture toughness test, temporary crown's fracture line located next to the screw hole while modified designs with metal support showed fracture line on the metal and its propagation along the metal-resin interface. 2. Wing and bulk structure didn't show significant difference in the fracture toughness (p>0.05), but wing structure showed stress concentration on the screw hole area compared to bulk structure which showed even stress distribution. 3. In the fracture toughness test after thermocycling, wing and bulk structure showed increased or similar results in metal supported area while off-metal area and temporary crown showed decreased results. 4. In the strain measurement after thermocycling, its value increased in the temporary and bulk structure. However, wing structure showed decreased value in the loading point while increased value in the screw hole area. Conclusion: Wing type design showed compatible result to the bulk type that its application with composite resin prosthesis to the implant dentistry is considered promising.

• The Korean Journal of Ecology
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• v.12 no.4
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• pp.285-295
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• 1989

This report is results of an investigation on the secondary succession and species diversity of the burned area. Fifty hectares of pine forest was burned by the crown fire of the spring (April 6) 1986. The results obtained from spring 1989 were summarized as follows: In the burned area , site and unburned area (U), the vascular plant fo 69 kinds, 49 kinds and 24 kinds were lsted respectively. The life form spectrum of burned area was H---e type, which is common type in most burned area and that unburned area, H---e type. The species diversity (H)and evenness index (e) of burned area (, site) were H=2.51, 1.65 and e=0.59, 0.44 and those of unburned area (U) were H=1.28 and e=0.40. The similarity index was the value of 0.594 in - and 0.236 in -U site. The similarity between and site was greater than between site and U site, and that between and U-site, The dominance index (c) of , and U-site was 0.16, 0.39 and 0.42 respectively. The succession degree (DS) of , and U-site was 244.0, 227.6 and 854.4 respectively. Soil pH, available phosphorous, and exchangeable potassium in the burned area were higher than those in the unburned area, and total nitrogen, organic carbon, and C/N ratio in the burned area were higher than those in the unburned area, and organic matter in the burned area was higher than that in the unburned area.

• Fire Science and Engineering
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• v.23 no.4
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• pp.32-39
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• 2009

In this study, 18 plots were selected for particular investigation on Gangneung area and Samcheok area and Uljin area, where forest fire was occurred after thinning in 2007. After selection, a relationship between a damage of forest fire and thinning were compared and analyzed. Many factor such as a damaged species, a thinning or non-thinning, a direction of forest fire head, DBH, a height of tree, a mortality of tree, a leeward scorching ratio, a crown damage ratio, a forest tree standing crop density, a crown base height, a leaving of thinning slash, a location of plot (GPS), elevation, an aspect of slope, an angle of slope, and a topography were measured. Therefore, we analyzed a relationship with forest fire. In the result of this analysis, it was founded that the leeward scorching ratio was 24.7% on thinning area whereas 60.2% on non-thinning area. Subsequently, leeward scorching ratio on thinning area was increased by about 35.5% more than on non-thinning area. In the result of analysis about tree species, a forest of pine tree was more damaged than forest of oak tree. The mortality of tree was increased by about 41.4% on non-thinning area. When stands were close to thinning slashes, these were more damaged by 10${\sim}$20% than other stands for increasing of amount of a combustion material. Especially, as potential of re-ignition increased for more cumulated thinning slash, it will be more important to require a method for a periodical removing or practical utilization of slash.