• Journal of Korean Society of Forest Science
• /
• v.81 no.4
• /
• pp.303-309
• /
• 1992

This study eras carried out to investigate the ecological changes on the plant community at erosion controlled area in Yoju-gun, Kyonggi-do. The results of the study were as follows : 1. The depth of organic matters in the soil profile from 4 to 14 years was estimated to be $Y_{(cm)}=0.436X_{(yr)}-0.931$(r=0.978), and 02 layer was $Y_{(cm)}=0.339_{(yr)}-0.931$ (r=0.954). 2. On upper plant layer. Alnus spp. was decreased, on an average, 32% of relative coverage, 12.4% of relative density and 16.8% of relative frequency in each plot for 3 years, as this area was damaged by Agelastica coerulea Baly for 2-3 years. 3. On upper plant layer, relative coverage of Pinus spp. was increased after 6, 7 years in erosion controlled area and was taked the highest plant (more then 40%) from 10 to 14 years. 4. On lower plant layer, relative density of Quercus ssp. (these species has not been planted and sown on erosin controlling) was increased all the plot. 5. The increase of the whole crown projection area was estimated to be $Y_{(m^2)}=18.020X_{(yr)}+18.834$(r=0.954) 6. The biomass was estimated to be 14.88t/ha on elapsed 6 years, 22.84t/ha on 8 years, 35.08t/ha on 10 years, 47.80t/ha on 12 years, 58.13t/ha on 14 years.

• The Korean Journal of Ecology
• /
• v.26 no.4
• /
• pp.209-214
• /
• 2003

In order to clarify the successional trend and its characteristics of plant community in abandoned field in Cheju Island, we investigated the seral changes of vegetation height, coverage, growth form, species richness, diversity and dominance index along with the time lapse, and then compared with those of mainland researches. And in order to seek the overall trend of vegetation changes, we used cluster, TWINSPAN and PCA ordination techniques. The succession was characterized by the lower species number, lower vegetation height, longer period of herb dominant and later invasion of tree species. These results may come from that ecological traits of Cheju Island itself, and ecosystem fragmented influences that block a seed (propagule) transport. Sere of the dominant species was shown as follows: Mazus japonicus(0.5∼1 years)→Conyza sumatrensis (2 years)→Artemisia princeps var. orientalis(4 years)→Artemisia princeps var. orientalis, indigofera pseudotinctoria(5 years)→Rosa multiflora, Miscanthus sinensis, etc.(8 years)→Miscanthus sinensis(12 years)→Boehmeria nivea, Pueraria thunbergiana etc.(15 years)→Mallotus japonicus(20 years)→Litsea japonica, Machilus thunbergii (20 years<). Abandoned fields were classified into three groups according to time lapse; earlier stage(0∼1 years), middle stage(2∼8 years) and later stage(8∼20 years).

• Journal of Chest Surgery
• /
• v.23 no.4
• /
• pp.731-735
• /
• 1990

Simultaneous and non simultaneous bilateral spontaneous pneumothorax patients[273] were reviewed retrospectively from April 1986 to March 1990 in the Dept. of Thoracic and Cardiovascular Surgery, Kyung Hee University Medical College. The incidence of bilateral spontaneous pneumothorax was 13.6%[37] and sexual distribution was male dominant [Male:33, Female:4]. The patients were classified into three major groups according to therapeutic methods: Group I [7]; who were treated with simultaneous bilateral operation for unilateral recurred spontaneous pneumothorax through median sternotomy. Mean age was 20.7 years[17 \ulcorner28] and follow up duration was 7.7 months [3 weeks \ulcorner2 years]. Group II [23];who were treated with staged lateral thoractomy, unilateral thoracotomy and non simultaneous contralateral closed thoracostomy, or simultaneous or non simultaneous bilateral closed thoracostomy. Mean age was 28.6 years [17 \ulcorner56] and follow up duration was 9.8 months[one week \ulcorner3.5 years]. Group III[10] ;who were treated with simultaneous bilateral operation for simultaneous or non simultaneous bilateral spontaneous pneumothorax through median sternotomy. Mean age was 21.4 years[17 \ulcorner28] and follow up duration was 12.8 months[2 weeks \ulcorner2.7 years]. Among the patients managed through median sternotomy simultaneously [Group I and III], there were visible blebs or bullous changed lesions mainly in the apicoposterior segment bilaterally in 15 patients[88.2%] Postoperative complications were 3 cases in Group II [wound infection:2 cases, temporary left wrist drop: one case] but none in Group I and III. Spontaneous pneumothorax recurred in 2 cases, one in Group II and another in Group III but none in Group I. 12 cases of 94 patients[12.8%o] who were treated with unilateral thoracotomy needed contralateral thoracotomy mean 14.9 months[7.5 \ulcorner 25 months] later. Mean age was 20.9 years [17 \ulcorner28]. In conclusion, simultaneous bilateral operation through median sternotomy should be considered in managements of spontaneous pneumothorax, especially in late teens and early twenties except young women for cosmetic reasons.

• Journal of Chest Surgery
• /
• v.19 no.1
• /
• pp.108-115
• /
• 1986

During 12 years period from 1974 to 1985, 76 valve replacement procedures were performed at Seoul National University Hospital in 67 pediatric patients aging up to 15 years [mean 12.3 years] and it was 7.3% of total valve replacement procedures in same period. Sixty seven patients were composed of 44 males and 23 females. Of the 67 patients, 43 patients had acquired valve lesions and 24 patients congenital valve lesions. Sixty cases received single valve replacement, 7 cases double or triple valve replacement and 9 cases redo-valve replacement. Sixty seven patients received 84 valves [65 bioprosthetic valves and 19 prosthetic valves by] 76 operations, Sixty three of 65 bioprosthetic valves had been replaced before 1983 and 15 of 19 prosthetic valves in recent 2 years. Eleven patients [14.6%] died within one month post-operatively and 8 patients [10.5%] during the follow-up period with the overall mortality rate of 25.1%. There were early post-operative complication of 23 cases [30.3%] and late post-operative complication of 27 cases [35.3%] with the total complication rate of 65.8%. In 58 patients received bioprosthetic valves, there were 14 cases of restenosis of replaced valves. Of the 14 cases of bioprosthetic valve restenosis, 8 cases received redo-valve replacement procedures without mortality in 1 5/12-5 years after initial operation but 4 cases died without reoperation and 2 cases lost during follow-up. The overall mortality and complication rate were still high but they markedly decreased during recent 2 years. So, in spite of its containing many problems, valve replacement in children is becoming safe and useful procedure in whom valve reconstructive procedures are impossible.

• Journal of Technologic Dentistry
• /
• v.11 no.1
• /
• pp.23-34
• /
• 1989

The great sudenn change of circle of dental laboratory technology brought mary discord between the new growing environmental group and the old group, In order to know the satisfactory degree of dental laboratory heads about all dental College, This Study was conducted for 49 detal technicians who graduated from junior laboratory heads in Seoul and Kyoung Gi area. The results are abtained as follow- 1. By age The degree of Satisfaction of items about all graduate dental technician were "41$\sim$45 age" group 26.53%), "46$\sim$50 age" group 22.45%, "36$\sim$40 age" group 18.36%, "31$\sim$35 age" group 12.24%, "51$\sim$55 age" group and "56$\sim$60 age" group 8.16% 60$\sim$age group 4.08% in order. 2. By Job Career. The Highest degree item out of Satisfaction about all graduated dental dental technician was 21$\sim$25 years group 28.5%, 16$\sim$20 years 20.4%, 11$\sim$15 years group 12.24%, 26$\sim$20%, 6$\sim$10 years group 4.08%, below 5 years group 2.04% in order. 3. By managing term of respondent's dental laboratory. The Satisfactory degree of items about all gradate technician were 7$\sim$10 years group 36.73% over 15 years group 22.45%, 11$\sim$14 years group 20.41%, 3$\sim$6 years group 14.29% below 2 years group 6.12% in order 4. By dental technician number of respondent's dental laboratory. The satisfactory degree intems about man were as follow; 6$\sim$9 persons group is 42.86 % The Satisfactory degree items about woman were one persons group in 34.69% 5. By born place The dental laboratory heads mean of inters about all dental technician were Seoul group 20.64 %, Kyoung Gi 17.20 %, Jen Nam group 14.99 % Chung Nam 9.5%in order 6. The satisfactory degree of items about all graduate dental technician were neither good nor bad group 32.65%, bad 6.12%, By ability of adaptaton, The satisfactory degree items about man were neither good nor bad group 42.86%, bad group 40.82%. The satisfactory degree of items about woman were neither good nor bad group 40.82% bad group 36.73%. 7. By sincerity. The satisfactory degree of items about man dental technician who graduated from Junior College were neither good nor bad group 52.02%, bad group 4.08, The satisfactory degree about woman dental technician graduated from Junior College were neither good nor bad group 42.86%, bad group 6.12%. 8. By ability of basical of items about man were bad group 40.82 %. The satisfactory degree about woman were 46.94%. 9. By cooperation relation ship. The satisfactory degree of items about man were neither good nor bad group 42.86%, bad group 10.20%. The satisfactory degree about woman were neither good nor bad group 42.86%, bad group 10.20 %. 10. By ability of work. The satisfactory degree of items about man were neither good nor bad group 48.98%, bad group 4.08%. The satisfactory degree about woman were neither good nor bad group 42.86%, bad group 6.12 %. 11. By the curriculum of the dental technician. The satisfactory degree of items about man were neither good nor bad group 67.35%, bad group 2.04%, The satisfactory degree about woman were neither good nor bad group 61.22%, bad group 6.12%. 12. By occupational satisfaction. The satisfactory degree of items about all graduate dental technician were fatisfied group 14.29%. By the out look of employment. The satisfactory degree of items about man greduate dental technician were neither good nor bad group 34.69 %, bad group 10.20%, about woman graduate dental technician were neither good nor bad group 44.90%, bad group 10.20%, Their employment prospect is not so bright or oprimistic due to the glut supply by graduates in the job-seeking market 13. The satisfactory rate on the artificial dental manufacturing world in terms of effects produced by juror College graduate dental technicians shared good group 40.82% bad group 2.04% 14. By cognition of the number of graduate dental technician. The satisfactory degree of dental laboratory heads about man graduate dental technician were too many group 38.78%, few group 6.12% about woman graduated dental technician were neither good nor bad group 30.6% few group 10,20%, The employment opportunities for the artifical dental technicians are getting decreased because of their excessive cumber in supply 15. The opinion regarding the initial salary. ranging from \160,000 to \200,000 for the junior college graduate dental technicians shared 57.14%. The top ratio, while the satisfaction reate on the academic study period of "3-year" group shared 22%, also the top ratio. 16. The improvement policy and prblematic issues presonted by the owner and operatore of atriticial dental manufacturing plants are as shown below First; The viewpoint that they contribute to the improvement of people's oral health in terms of their mission as artificial dental technicians. Second: The cultivation of basic technical ability to cope with clinical practice upon graduation Third; They require guidance in study and research in their filed of profession, that tray may beable to estaclish a from theory.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.50 no.3
• /
• pp.123-133
• /
• 2024

Dentoalveolar (DA) trauma, which can involve tooth, alveolar bone, and surrounding soft tissues, is a significant dentofacial emergency. In emergency settings, physicians might lack comprehensive knowledge of timely procedures, causing delays for specialist referral. This systematic review assesses the literature on isolated DA fractures, emphasizing intervention timing and splinting techniques and duration in both children and adults. This systematic review adhered to PRISMA guidelines and involved a thorough search across PubMed, Google Scholar, Semantic Scholar, and the Cochrane Library from January 1980 to December 2022. Inclusion and exclusion criteria guided study selection, with data extraction and analysis centered on demographics, etiology, injury site, diagnostics, treatment timelines, and outcomes in pediatric (2-12 years) and adult (>12 years) populations. This review analyzed 26 studies, categorized by age into pediatrics (2-12 years) and adults (>12 years). Falls were a common etiology, primarily affecting the anterior maxilla. Immediate management involved replantation, repositioning, and splinting within 24 hours (pediatric) or 48 hours (adult). Composite resin-bonded splints were common. Endodontic treatment was done within a timeframe of 3 days to 12 weeks for children and 2-12 weeks for adults. Tailored management based on patient age, tooth development stage, time elapsed, and resource availability is essential.

• The Korean Journal of Ecology
• /
• v.21 no.6
• /
• pp.809-814
• /
• 1998

Changes of annual seed production related to climate change were studied for 12 years in Piagol, a riparian valley in Mt. Jiri. Sixty-four seed traps (sized 0.5 ${\times}$ 0.5 $m^{2}$) were set up on the forest floor of surveyed area. Seeds were collected from these traps at an interval of 15 days from September to November since 1984. Vegetation of the study area was mainly consisted of the naturally regenerated Carpinus tschonoskii in the tree layer. Acer mono, Quercus serrata, Carpinus laxiflora and Symplocos chinensis also appeared in the same layer. Maximum production occurred in 1984 and 1994. As a result of comparing seed production with local climate factors for 12 years, seed productivity and the year of maximum production of Carpinus forest were merely related with precipitation, air temperature and duration of sunshine among local climate factors. Duration of sunshine was, however, not contributed to periodically high productivity of seed of riparian valley carpinus forest.

• Architectural research
• /
• v.14 no.3
• /
• pp.99-108
• /
• 2012

An innovative multi-story Semi-Active Tuned Mass Damper (SATMD) building system is proposed to control seismic response of existing structures. The application of adding new stories as large tuned mass and semi-active (SA) resettable actuators as central features of the control scheme is derived. For the effective control of the structures, the optimal tuning parameters are considered for the large mass ratio, for which a previously proposed equation is used and the practical optimal stiffness is allocated to the actuator stiffness and rubber bearing stiffness. A two-degree-of freedom (2-DOF) model is adopted to verify the principal efficiency of the suggested structural control concept. The simulations for this study utilizes the three ground motions, from SAC project, having probability of exceedance of 50% in 50 years, 10% in 50 years, and 2% in 50 years for the Los Angeles region. 12-story moment resisting frames, which are modified as '12+2' and '12+4' story structures, are investigated to assess the viability and effectiveness of the system that aims to reduce the response of the buildings to earthquakes. The control ability of the SATMD scheme is compared to that of an uncontrolled and an ideal Passive Tuned Mass Damper (PTMD) building system. From the performance results of suggested '12+2' and '12+4' story retrofitting case studies, SATMD systems shows significant promise for application of structural control where extra stories might be added.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.1 no.1
• /
• pp.19-29
• /
• 1974

Surveying the root resorption of the mandibular deciduous teeth in 967 children, (Male 493 Female 474) from 3 to 12 years old by orthopantomography, the author obtained the following results. 1) Female in the root resorption of the deciduous teeth was earlier than male. 2) The stages of initial resorption of the deciduous teeth were as follow. central incisor 4 years lateral incisor 4 years 2 months cuspid 6 years first decid uous molar 6 years second deciduous molar 6 years 5 months 3) The exfoliational stages ($R_5$) of the deciduous teeth were as follow. central incisor 6 years 8 months lateral incisor 7 years 2 months cuspid 9 years 10 months first deciduous molar 10 years 3 months second deciduous molar 11 years.

• The korean journal of orthodontics
• /
• v.4 no.1
• /
• pp.31-40
• /
• 1974

The age of maximum growth increments-the adolescent spurt-is not only of developmental interest but is used as a marker for timing other growth events. And the mandibular growth rate follows the general growth curve, it is essential for an orthodontist to take the current and exact information about physical growth of patients. The author measured and studied the body height and weight of 11,694 children living in Seoul, and calculated out the mean, standard deviation, coefficient value, annual increments, percentage increments of each value, and made diagram to compare it with others. 1. The growth curve shows linear increment tendency until 17 years of age in male, 15 years in female. 2. The annual increment curves of body height and weight reveals the most peak value in 14-16 years in male and 11-14 years in female. 3. During 11-14 years of age, female growth exceed the male growth in the body height growth. And in weight growth, female growth exceed the male growth during 6-7 years and 11-12 years to show twice crossing. 4. It seemed that until 11-12 years in male and until 9-10 years in female the height growth show the priority to weight growth. And from 17 years in male and 15 years in female the body growth reveals the balanced growth pattern. 5. The time of changes of standard deviation curves of body height and weight coincided with that of annual increments. 6. The prominent high value of body height and weight in the comparison with other data may be due to the secioeconomical and nutritional, environmental influence. 7. The growth accerlation phenomena was detectable.