• The Journal of Korean Academy of Prosthodontics
• /
• v.49 no.4
• /
• pp.316-323
• /
• 2011

Purpose: The purpose of this study was to investigate the effect of different thread designs on the marginal bone stresses around dental implant. Materials and methods: Standard ITI implant(ITI Dental Implant System; Straumann AG, Waldenburg, Switzerland), 4.1 mm in diameter and 10 mm in length, was selected as control. Test implants of four different thread patterns were created based on control implant, i.e. maintaining all geometrical design of control implant except thread pattern. Four thread designs used in test implants include (1) small V-shape screw (model A), (2) large V-shape screw (model B), (3) buttress screw (model C), and (4) trapezoid screw (model D). Surface area for unit length of implant was 14.4 $mm^2$ (control), 21.7 (small V-shape screw), 20.6 (large V-shape screw), 17.0 (buttress screw) and 28.7 $mm^2$ (trapezoid screw). Finite element models of implant/bone complex were created using an axisymmetric scheme with the use of NISA II/DISPLAY III (Engineering Mechanics Research Corporation, Troy, MI, USA). A load of 100 N applied to the central node on the crown top either in parallel direction or at 30 degree to the implant axis (in order to apply non-axial load to the implant NKTP type 34 element was employed). Quantification and comparison of the peak stress in the marginal bone of each implant model was made using a series of regression analyses based on the stress data calculated at the 5 reference points which were set at 0.2, 0.4, 0.6, 0.8 and 1.0 mm from implant wall on the marginal bone surface. Results: Results showed that although severe stress concentration on the marginal bone cannot be avoided a substantial reduction in the peak stress is achievable using different thread design. The peak marginal bone stresses under vertical loading condition were 7.84, 6.45, 5.96, 6.85, 5.39 MPa for control and model A, B, C and D, respectively. And 29.18, 26.45, 25.12, 27.37, 23.58 MPa when subject to inclined loading. Conclusion: It was concluded that the thread design is an important influential factor to the marginal bone stresses.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.31 no.4
• /
• pp.651-658
• /
• 2004

Runx2 is a transcription factor in homologous with Drosophila runt gene and it is essential for bone formation during embryogenesis and a critical gene for osteoblast differentiation and osteoblast function. Runx2-haploinsufficency causes cleidocranial dysplasia (CCD). CCD is an autosomal-dominant inherited disorder characterized by hypoplastic clevicle and delayed ossification in fontanelles and wormian bones. Dental defects are possibly shown to CCD patients : multiple supernumerary teeth, irregular and compressed permanent tooth crowns, hypoplastic and hypomineralized defects in enamel and dentin, an excess of epithelial root remnants, the absence of cellular cementum, and abnormally shaped roots. In addition, delayed eruption of the secondary dentition is a constant finding. The aim of this study is to evaluate the role of Runx2 in the tooth development and eruption through analyzing the expression pattern of Runx2 by in situ hybridization during crown (late bell stage) and root formation of tooth, using postnatal day 1, 4, 7, 14 and 21 mice mandibular molar teeth. mRNA of Runx2-full length is expressed in dental follicle and surrounding tissue at postnatal day1 and 4. At postnatal day 7, it is expressed in ameloblasts of occlusal surface of enamel and bone area surrounding the tooth. In comparison with previous stage, at postnatal day 14, it is expressed in ameloblasts of proximal surface of enamel. At postnatal day 21 it's expression is observed only in bone area. mRNA of Runx2-typeII is not expressed. At postnatal day 1 and 7. At postnatal day 14 and 21, it's expression is observed in the bone area. In this study, we suggest that Runx2 have a relation of ameloblasts differentiation and an important role to tooth eruption made by dental follicle during intraosseous eruption stage. Also we can confirm that Runx2 has a role to bone formation.

• Journal of Life Science
• /
• v.26 no.8
• /
• pp.904-910
• /
• 2016

Complex traits are determined by the combined effects of many loci and are affected by gene networks or biological pathways. Systems biology approaches have an important role in the identification of candidate genes related to complex diseases or traits at the system level. The gene network analysis has been performed by diverse types of methods such as gene co-expression, gene regulatory relationships, protein-protein interaction (PPI) and genetic networks. Moreover, the network-based methods were described for predicting gene functions such as graph theoretic method, neighborhood counting based methods and weighted function. However, there are a limited number of researches in livestock. The present study systemically analyzed genes associated with 102 types of economic traits based on the Animal Trait Ontology (ATO) and identified their relationships based on the gene co-expression network and PPI network in cattle. Then, we constructed the two types of gene network databases and network visualization system (http://www.nabc.go.kr/cg). We used a gene co-expression network analysis from the bovine expression value of bovine genes to generate gene co-expression network. PPI network was constructed from Human protein reference database based on the orthologous relationship between human and cattle. Finally, candidate genes and their network relationships were identified in each trait. They were typologically centered with large degree and betweenness centrality (BC) value in the gene network. The ontle program was applied to generate the database and to visualize the gene network results. This information would serve as valuable resources for exploiting genomic functions that influence economically and agriculturally important traits in cattle.

• Journal of the Korean Geographical Society
• /
• v.31 no.1
• /
• pp.1-18
• /
• 1996

This study examines the spatial characteristics of postal office patronage in rural areas. in the light of future possible relocation and closures of the postal facilities. Most of private services have flown out small rural central places due to the decrease of supporting population, and there consequently remain only a few public services including government-run post offices at the Myon seats, the lowest level among rural central places in Korea. The small local population and its further decline undermine the rationale for maintaining such public services in depleted rural areas. For the worse of it, the government recently plans to transform the postal system to a quasi-private, corporational structure. One can fear that the profit-seeking nature of the new postal corporation will inevitably force to close many of such small rural facilities. The study first analysed nation-wide censuses of postal offices for the years of 1986 and 1992. The postal services examined are per capita number of postal stamps and revenue stamps sold, and letters, parcels, telegrams and monetary transactions handled at the post offices. It is found that, while the usage of postal services has increased substantially throughout the nation during the period of 1986-1992, the increment has largely been occurred by urban post offices rather than by those in Gun seats (i.e., rural counties); and that the gap of the service levels between urban and rural post offices is ever widening. The study further examined the service differentials among the post offices within rural counties to find that those post offices adjacent to the county (Gun) seats and larger urban centers rendered less amount of services than remote rural post offices, indicating that rural residents tend to partonize larger centers more and more than local Myon seats. At the second stage of the study, questionnaire surveys were conducted in Muju, Kimpo, and Hongsung-Gun's. These three counties are meant to represent respectively the remote, suburban, and intermediary counties in Korea. The analyses of survey data reveal that the postal hinterlands of the county seats extend to much of nearby Myons, the subdivisions of a Gun. It is also found that the extent of postal hinterlands of the three counties and the magnitude of patronage and quite different from each other depending upon the topography, population density, and the propinquity of the counties to metropolitan centers. The findings suggest to reappraise the current flat allocation scheme of public facilites to each of rural subdivisions throughout the nation. A detailed analysis on the travel behavior of the survey respondents yields that age is the most salient variable to distinguish activity spaces of rural residents. The activity spaces of older respondents tend to be more limited within their Myon, whereas those of younger respondents extend across the Myon boundary, toward the central towns and even distant larger cities. The very existence of several activity spaces in rural areas calls for an attention in the future locational decisions of public facilities. The locational criteria, employed by the Ministry of Communication of Korean government to establish a post office, are the size of hinterland population and the distance from adjacent postal facilities. The present study findings suggest two additional criteria: the order in rural central place hierarchy and the propinquity to the upper-level centers of the central hierarchy. These old and new criteria are complementary each other in that the former criteria are employed to determine new office locations, whereas the latter are appropriate to determine facility relocation and closures.

• Journal of the Korea Institute of Building Construction
• /
• v.9 no.4
• /
• pp.119-129
• /
• 2009

Building construction trends have been changed dramatically in terms of size and mass. With the need to maximize land usage, there has been an increase in the construction of high-rise buildings. This affects not only the entire construction duration and cost, but also subsequent construction activities, such as work to increase underground facilities and in reclamation land area construction. These types of site conditions require soft ground reinforcement and the proper uplift water pressure treatment. In general, two kinds of methods have been used for uplift water pressure treatment systems. However, there have been some problems arising as the result of a lack of research and analysis on underground construction techniques, and a reliance on experiments over actual survey and analysis of site conditions. This paper focused on the problems of conventional selection procedure, by analyzing drawings and proposing a kind of modeling for a reasonable procedure. The results were applied to OO project as a sample construction case to be verified in this research. The initial plan in the case project was the Rock Anchor System. However, as there were terrible miscalculations of basic site conditions that had an extraordinary influence on the underground water level, such as the site's proximity to the Han-river, it was necessary to change the plan to include apermanent drainage system. This achieved a direct construction cost reduction \ 406,702,000 and a maximum sayings of 4% of operational cost, based on the 50-year building Life Cycle Cost.

• Journal of Korean Society of Forest Science
• /
• v.98 no.1
• /
• pp.94-105
• /
• 2009

Black locust (Robinia pseudoacacia) stand is representative lowland exotic plantation with low ecological quality and arrested succession in South Korea. To facilitate succession and restore natural vegetation, small canopy gaps (${\sim}57m^2$), which can modify minimally structural variables and reduce restoration related disturbances on stand, was established in the black locust stand, and oak (Quercus serrata) seedlings were introduced in the gap. Two types of varying levels were introduced for gap creation; cutting (C) and girdling (G) on canopies. Understory removal (CU and GU) treatment was applied as subtypes of structural modification. Growth (diameter, height and leaf area) of target species and responses (species composition, diversity and coverage) of understory community were monitored during study years (2007~2008). Canopy openness was different significantly among treatments but not for light availability. Based on the result of logistic regression, growth of height and leaf area of seedlings were significant variables on seedling survival. Height and leaf area of seedlings were increased during study years, although radial growth was reduced. During study years, there were no significant differences in species composition and diversity, and total coverage increased about 20%. Increase of resources by gap creation and understory removal likely affect growth of target species. Small gap creation was effective to reduce understory responses in composition and diverstiy. Synthesized, growth of target species and responses of understory community to small canopy gap creation exhibited, in short term, possibility of utilization in alternative forest restoration and management option. Long-term monitoring is necessary to certificate effect of artificial gap creation on forest restoration.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.36 no.5
• /
• pp.73-81
• /
• 2008

The purpose of this study is to create a database of the use of landscape greenery that surrounds commercial buildings in Seoul. The method of this study was: to review preceding studies and related laws, survey areas, measure trees, and analyze the results. The 20 representative sites were specifically investigated to measure the width, direction, and environment of planting conditions. To analyze the greens adjacent to the building, the greens were divided into three types: front greenery, side greenery, and rear greenery. The study surveyed the distance from trees to adjacent buildings, and their planting conditions. The results of this study are as follows. First, 45% of the front greenery and 30% of the rear greenery were not established, but 19 of the 20 side greens were. Second, 13 of the 44 green areas adjacent to commercial buildings were under 1m in width. Most side greenery was belt -shape and unrelated to the features of the site or building. Third, the average distance from trees to buildings was 0.76m, indicating that most trees were planted too close to the buildings. Fourth, of the 30 trees utilized, the species breakdown was: 8 evergreen trees, 15 deciduous trees, and 7 shrubs. For the most part, planting patterns were similar for all species. Fifth, most sites were ill-suited to tree growth, because crown shape, planting conditions, and light conditions, etc., had not been considered. Based on these results, it is suggested that more specific, subdivided standards for planting conditions should be established. For example, building plans should include a green area that is at least one meter in width. In addition, according to the location and type(closing/opening) of the greenery adjacent to the buildings, suitable management programs and supervision protocol should be adopted.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.40 no.1
• /
• pp.43-56
• /
• 2012

The purpose of this study was to propose management strategies through aesthetic landscape assessments for landscape units in the Han River riparian(HRR) area. First, this research reclassified the HRR into "natural," "artificial," "agricultural," and mixed landscape types and selected 37 representative case areas(about $1km{\times}1km$). This study found 71 landscape units in consideration of topography and land surface classification. Landscape assessment consisted of landscape quality and landscape integration assessment. The criteria for assessing landscape quality were "naturalness," "interest," "uniqueness," and "landscape function." "Landscape quality" was ranked into five grades using a matrix. The landscape integration assessment consisted of an inner integration assessment in each landscape unit and outer integration assessment among landscape units. As a result of the field study, case sites were found to have 4,288 landscape units and an area of $42.8km^2$. The forest area was found to have the most space with $11,580,905m^2$(27.1%), while the wet lands had just $52,348m^2$(0.1%). In the landscape quality assessment, about 30.5% of the total area consisted of landscape units that scored highest in "naturalness". In the landscape integration assessment, about 39.3% of the total area consisted of landscape units which scored highest in "integration", denoting visual interrelation and harmony. The existence of disparities in landscape quality in accordance with the form of the landscaping was determined using a Oneway ANOVA, with "naturalistic" landscaping scoring the highest and "artificial" landscaping scoring lowest. This study may contribute to making the HRR area a more ecologically sound and visually attractive landscape space. It is recommended that the aesthetical and ecological value of the landscape unit should be assessed simultaneously in the future.

• Journal of the Korean Institute of Traditional Landscape Architecture
• /
• v.38 no.2
• /
• pp.14-30
• /
• 2020

This study focuses on the fact that pictorial maps in the late Joseon Dynasty were conceptual diagrams with the place names perceived by the people at the time of their production. In this regard, targeting on five pictorial maps, the humanistic landscape characteristics of Pyongyang, which had cultural identities such as a historically old, commercial, and Pungnyu(appreciation for the arts) city, were derived as follows. First, the historic legitimacy of Pyongyang Castle was represented by ritual and religious facilities. They include 'Dangunjeon' and 'Gijagung' related to the nation founder, 'Munmujeong': the remains of Goguryeo, 'Sajikdan' & 'Pyongyanggangdan': the place of the national rites, Hyanggyo and Seowon: education & rite functions, Buddhism and Taoist facilities, 'Yongsindang', 'Sanshindang', and 'Jesindan': folk religion facilities. Gija-related facilities, which became symbols of Pyongyang due to the importance of Small-Sinocentrism and Gija dignity tendency, were distributed throughout Pyongyang Castle though, the facilities related to King Dongmyeong of Goguryeo and the spaces of religion praying for blessings are spread in Bukseong and on the riverside of Daedonggang each. Second, as a Pyongando Province's economic center, Pyongyang's commercial landscape was represented by logistics and transportation facilities. The Daedonggang River, which was in charge of transportation functions, had many decks such as 'Yangmyeongpo', 'Cheongryongpo' and 'Waeseongjin' and bridges, such as 'Yeongjegyo' and 'Gangdonggyo', which connected major transportation routes. The road network was created in Oeseong area to facilitate logistics transportation and management, and many warehouses named after the jurisdiction of Pyongyangbu were distributed near the roads and Provincial Offices of the main gates. In addition, it was characterized by the urban area systematically divided with hierarchical roads, 'Bukjangnim' of willow trees planted on the main entrance roads of Pyongyang Castle, a linear landscape created by 'Simnijangnim' consisting of mixed forests with elm trees. Third, Pungnyu City is realized by the distribution of amusement facilities. The riverside of Daedonggang adjacent to Naeseong exhibits characteristics of artificial landscape such as a canal leading to the inside of the castle, a docking facility with embankments, and a port with cargo ships anchored. However, Bukseong of the natural surroundings had numerous pavilions and platforms such as 'Bubyeongnu', 'Eulmildae', 'Choeseungdae', 'Jebyeokjeong' and engraved letters such as 'Cheongnyubyeok', 'Jangbangho'. 'Osunjeong', 'Byeogwolji', 'Banwolji' near 'Sachang', and 'Aeryeondang', built on the island of a square pond, created waterscape in Naeseong invisible from the Daedonggang, and for practical purposes, ponds and repeated willow vegetation landscape related to Gija were placed in the western rampart of Jungseong. In addition, 'Seonyeondong', a cemetery of Gisaeng, located near by Chilseongmun, was used as poem titles and themes by literary people, contributing to the creation of the Pungnyu image of Pyongyang.

• Journal of the Korean association of regional geographers
• /
• v.7 no.3
• /
• pp.91-106
• /
• 2001

Local government takes an active role in the (re)making of local socio-economic space. To support such an argument, the three different actions by the local government of Taegu, urban planning and local industrial districts, the establishment of special educational institutions, and textile festival are analyzed. The division of the city's space into residential, commercial, and industrial area by local government constrained the location of local manufacturing industries. It also forced textile industry to move to the outskirts of Taegu. As the education level in South Korea rose after the late 1970s, the local government of Taegu as well as local industrial capitalists had to do something to acquire a stable supply of labor to local manufacturing industries, particularly textile one. After the late 1970s, the special classes for the education of local workers, especially textile ones were established within vocational high school and company-operated high schools were also built in Taegu. Finally, local government started a program of textile festival in 1985. Through textile festival, local government as well as local textile business people tried to reproduce textile industry as the main economic activity of Taegu.