• Korean Journal of Agricultural and Forest Meteorology
• /
• v.5 no.1
• /
• pp.30-35
• /
• 2003

The study of the scars formed on the bark of pine trees damaged by forest fire was carried out in the burned area of Samchuk and Donghae in 2000. Fire scars were formed on the bark of trees when fire passed by the tree. Fire scarring is usually found on the windward and leeward sides of the tree. Fire spread was analyzed topographically using the fire scars formed at the tree stem. Fire spread was closely related to the shape, slope and direction of the forestland. Four fire direction types are classified according to the shapes of the forestland. The height of the fire scar was higher on the leeward side than on the windward side of the trees studied. The burnt area of the total bark of the tree was over 30% in dead trees and below 12% in living trees. The regression model of the burnt stem area using the height of the fire scar, the diameter of breast height and the height of tree was Y=-2.484${\times}$Height＋0.04199${\times}$D.B.H-1.686${\times}$Windward＋11.172${\times}$Leeward＋23.432(r=0.936, F=409.968, P＞0.0001).

• Journal of Korean Society of Forest Science
• /
• v.111 no.4
• /
• pp.482-489
• /
• 2022

This study aimed to determine the optimal planting density of Fraxinus rhynchophylla assessed from the early growth performance at various planting densities over the 7-year period after planting. The study site was in Pyeongchang County, South Korea, and seedlings of 2-year-old (bare-root seedlings) F. rhynchophylla were planted at four densities (3,000, 5,000, 7,000, and 10,000 trees ha^-1) in March 2015. The survival rate, root-collar diameter (RCD), and height (H) were measured from 2015 to 2021, and the H/D (H/RCD) ratio and stem volume were calculated. The survival rate (84-97%) and H/D ratio (54.5-59.2%) were not affected by the planting density during the study period, but the RCD, H, and stem volume were significantly higher for 7,000 trees ha^-1 than for other planting densities. Especially, the stem volume (cm³ tree^-1) at 7 years after planting was highest for 7,000 trees ha^-1 (1,356.1), followed by 10,000 trees ha^-1 (958.6), 5,000 trees ha^-1 (773.0), and 3,000 trees ha^-1 (579.5). As the planting density increased, F. rhynchophylla seedlings showed initial rapid growth due to light competition, but relatively low growth at excessive planting densities. In the future, use of a suitable planting density considering planting costs should provide outstanding growth performance of F. rhynchophylla on plantations.

• Journal of Digital Convergence
• /
• v.11 no.9
• /
• pp.229-238
• /
• 2013

Out-of-hospital cardiac arrest is a major public health problem in Korea. The survival rate to discharge remains at approximately 3.5% and only 1% have good neurological function. To increase the survival rate, prehospital care should restore spontaneous circulation. The purpose of this study was to analyze the factors associated with return of spontaneous circulation(ROSC) after out-of-hospital cardiac arrest. Data used for this study were collected from KCDC Out-of-Hospital Cardiac Arrest Surveillance 2009. As for the results of decision tree analysis, it is clear that prehospital CPR, cardiac arrest witness, activity, past history(cancer/heart disease/stroke), place, bystander CPR, response time, age, etc are significant contributing factors in ROSC. Among 16 cardiac arrest types from decision tree classification, the ROSC rate of type 1 is the highest(29.6%). Also notable is the fact that bystander CPR was strongly correlated with ROSC of patents with cardiac arrest occurring in non-public places. Community resources should be concentrated on increasing bystander CPR and early prehospital emergency care.

• The Korean Journal of Quaternary Research
• /
• v.10 no.1
• /
• pp.1-18
• /
• 1996

한반도 쌍자엽식물의 시·공간적 분포역을 식물화석자료를 바탕으로 분석한결과에 따르면 우리나라에서 발견된 가장오래된 쌍자엽식물은 중생대 백악기의 Platanus, Viburnum, Populophyllum등이다. 당시에 남한에서는 17속의 쌍자엽식물이 보고되었으며 그 중 9속(버즘나무 Platanus, 분꽃나무 Viburnum, 버드나무 Salix, 사시나무 Populus, 녹나무 Cinnamomum 감탕나무 Ilex, 장구밤나무 Grewia, 두릅나무 Aralia, 생강나무 Lindera)은 현 재에도 자연적으로 분포한다, 우리나라의 신생대 제3기 팔레오세와 에오세에 대한 화석정보 는 불분명하다. 올리고세의 쌍자엽식물은 황해 봉산에서 12속이 발견되며 그중 11속은 아직 도 자라고 있다. 마이오세에는 북한의 gkarud도와 강원도의 7곳과 남한의 경북과 강원의 4 곳에서 72속의 쌍자엽식물이 출현했으며 16속(Engelhardtia, planera, Hamamelis, Porana, Sassafras, Parrotia, Comptonia, Hemitrapa, Nothofagus, Erica, Pasania, Cryptocary, Phoebe, Entada, Carpites, Trochodendron)을 제외한 나머지 56속은 현생한다. 신생대 제4기 플라이스토세 동안 복한 전역의 7곳과 남한 전역의 10곳에서 53속의 쌍자엽식물이 산출되었 으며 그 중 Engelhardtia, raphidephis, Sapium등 3속을 제외한 모든속이 아직도 자연적으로 분포한다. 홀로세에는 남한의 14곳에서 29속의 쌍자엽식물이 출토되었는데 Lespidobalanus 를 제외한 나머지는 지금도 잘 자라고 있다. 요약하면 한반도에 중생대 백악기에 쌍자엽식 물이 출현한 이래 신생대 제3기 올리고세와 마이오세 그리고 신생대 제4기 플라이스토세와 홀로세까지 큰 변화없이 식물상과 식생이 지속적으로 명맥이 유지되고 번성하였다, 이는 한 반도가 여러 차례가 기후 변화에 따라 식생대의 이동은 있었으나 식물상의 멸종을 가져올 정도의 환경적 격변을 겪지 않고 비교적 안정적인 환경이 장기간 지속되었음을 의미한다. 아울러 기후가 변화할 때마다 식물들리 서식, 생존할수 있는 다양한 피난처가 한반도의 도 처에 산재되어 있었음을 뜻한다,.

• Journal of Korea Society of Industrial Information Systems
• /
• v.28 no.2
• /
• pp.1-9
• /
• 2023

Research using AI and big data is also being actively conducted in the health and medical fields such as disease diagnosis and treatment. Most of the existing research data used cohort data from research institutes or some patient data. In this paper, the difference in the prediction rate of survival and the factors affecting survival between breast cancer patients in their 40~50s and other age groups was revealed using health insurance review claim data held by the HIRA. As a result, the accuracy of predicting patients' survival was 0.93 on average in their 40~50s, higher than 0.86 in their 60~80s. In terms of that factor, the number of treatments was high for those in their 40~50s, and age was high for those in their 60~80s. Performance comparison with previous studies, the average precision was 0.90, which was higher than 0.81 of the existing paper. As a result of performance comparison by applied algorithm, the overall average precision of Decision Tree, Random Forest, and Gradient Boosting was 0.90, and the recall was 1.0, and the precision of multi-layer perceptrons was 0.89, and the recall was 1.0. I hope that more research will be conducted using machine learning automation(Auto ML) tools for non-professionals to enhance the use of the value for health insurance review claim data held by the HIRA.

• Korean Journal of Plant Resources
• /
• v.24 no.4
• /
• pp.438-444
• /
• 2011

This study was conducted to investigate temperature effect on seed germination behaviors and seed viability changes by drying periods of three Ulmus species (Ulmus davidiana var. japonica (Rehder) Nakai, U. pumila L., and U. parvifolia Jacq.) distributed in Korea. Statistical analysis showed that temperature had a significant effect on mean germination time in three Ulmus species, but its effect on germination percentage was only shown in U. parvifolia (p<0.01). U. davidiana var. japonica and U. pumila germinated relatively consistent in all temperature conditions, especially the latter showed high germination behaviors in low temperatures (10-15$^{\circ}C$). U. parvifolia germinated well in high temperature (25$^{\circ}C$), while this species rarely germinated in low temperature conditions (10-20$^{\circ}C$). The results confirm that seeds of U. pumila and U. parvifolia are orthodox seeds which can be stored under 4-8% moisture condition, and U. davidiana var. japonica seed is recalcitrant seed which is difficult to store for a long time. In conclusion, these differences of the germination behaviors for three Ulmus species seem to be adaptive regimes of their natural habitats, respectively.

• Korean Journal of Environment and Ecology
• /
• v.38 no.2
• /
• pp.127-142
• /
• 2024

This study aimed to understand the interrelationships between tree species in plant communities through Plant Social Network (PSN) analysis using a large amount of vegetation data surveyed in an island area belonging to a warm-temperate boreal forest. The Machilus thunbergii, Castanopsis sieboldii, and Ligustrum japonicum, which belong to the canopy layer, Pittosporum tobira and Ardisia japonica, which belong to the shrub layer and Trachelospermum asiaticum and Stauntonia hexaphylla, which belong to the vines, appearing in evergreen broad-leaved climax forest community, showed strong positive association(+) with each other. These tree species had a negative association or no friendly relationship with deciduous broad-leaved species due to the large difference in location environments. Divided into 4 group modularizations in the PSN sociogram, evergreen broad-leaved tree species in Group I and deciduous broad-leaved tree species in Group II showed high centrality and connectivity. It was analyzed that the arrangement of tree species (nodes) and the degree of connection (grouping) of the sociogram can indirectly estimate environmental factors and characteristics of plant communities like DCA. Tree species with high centrality and influence in the PSN included T. asiaticum, Eurya japonica, Lindera obtusiloba, and Styrax japonicus. These tree species are common with a wide range of ecological niches and appear to have the characteristics and survival strategies of opportunistic species that commonly appear in forest gaps and damaged areas. They will play a major role in inter-species interactions and structural and functional changes in plant communities. In the future, long-term research and in-depth discussions are needed to determine how these species actually influence plant community changes through interactions

• Korean Journal of Plant Tissue Culture
• /
• v.22 no.6
• /
• pp.329-334
• /
• 1995

Transformation system of rolC gene, dwarf gene in Lycium chinenese Mill. established by using system. Pin-punctured leaves induced numerous adventious buds in abaxial side when cultured on 3/2 MS medium containing 2.0 mg/L zeatin. Survival rate and shoot regeneration frequency of leaf explants decreased as kanamycin sulfate level increased. Shoot buds were not regenerated on 3/2 MS medium containing 10 mg/L kanamycin sulfate and 2.0 mg/L zeaein. Of the level tested, 10 mg/L of kanamycin sulfate was optimum in selection of kanamycin sulfate resistant plant. Co-culture time of bacteria and leaf explants was affected at the frequency of shoot regeneration and survival of leaf explants. Leaf explants co-cultivated during above 48hr severely decreased survival rate and shooting rate. Best result on survival rate and shooting rate were obtained when exposed for 24 h. 80 explants of 105 leaf explants survived on 3/2 MS medium containing 2.0 mg/L zeatin and 10 mg/L kanamycin sulfate, and 15 shoots was regenerated on the same medium. To select kanamycin sulfate resistant plant, regenerate as cultured on 3/2 MS medium containing 10 mg/L kanamycin sulfate, and obtained 5 kanamycin resistant plants. Southern blot analysis conformed that the rolC gene was incorporated into the genomic DNA of kanamycin resistant plants.

• Korean Journal of Clinical Laboratory Science
• /
• v.53 no.4
• /
• pp.363-370
• /
• 2021

This study was conducted to evaluate the dermal cytotoxicity of lead acetate (LA) and other heavy metal compounds, and the protective effect of Lespedeza bicolor (LB) extract on LA-induced cytotoxicity in cultured B16-/F10 melanoma cells. The study evaluated the antioxidative effects of LB due to its electron-donating ability (EDA), inhibitory effects on melanization and improving cell viability. LA significantly decreased cell viability in a dose-dependent manner, and the XTT₅₀ value was determined at 52.7 µM in the studied cultures. Based on the Borenfreund and Puerner's toxicity criteria, LA was estimated to be highly cytotoxic. LA-induced cytotoxicity and cell damage was reversed by the antioxidant activity of kaempferol (KAE), thereby remarkably improving cell viability. A study of the protective effects of the LB extract on LA-induced cytotoxicity showed that the LB extract remarkably increased cell viability in the LA-treated group, and also inhibited the EDA and the total amount of melanin. The above results suggest oxidative stress-mediated cytotoxicity of LA. In the study, LB extract effectively prevented LA-induced cytotoxicity via its antioxidative activity and inhibition of melanization. In conclusion, natural resources like LB extracts may be useful agents for the prevention of oxidative stress-mediated cytotoxicity and melanization by heavy metallic compounds such as LA.

• Journal of Korean Society of Forest Science
• /
• v.79 no.1
• /
• pp.33-41
• /
• 1990

The purpose of this study is to investigate the developmental process of plant community during the secondary succession through the analysis of floristic composition, life form etcectra in burned site, and the structure of forest stand before forest fire occurrence was estimated by the method of anatomical wood identification for dead trees in burned site, Cheisuk-bong in Mt. Chiri of Korea. Plant community before forest fire occurrence was estimated the high mountain conifer stand of the last successional stage to consist of Pinus koraiensis(75%), Abies koreana(15%) and Picea jezoensis(10%), and Betula costata was survived only one species after forest fire occurrence. The total number of plant species in the investigated area was 19 families and 23 species that was identified. The dominate species in burned site were Festuca ovina and Arrhenatherum elatius, Carex humilis, Ligularia fischeri etcectra in the investigated area flora. The life form of plant in burned site was the erect from 47.8%, the tufted from 30.4%, the branched and the prostrate from was both 8.7%, It was assumed that dominant species in the burned sites were Gramineae (Festuca ovina, Arrhenatherum elatius), Carex humilis ${\rightarrow}$Sorbus commixta, Rhododendron schrippenbachii, Sambucus williamsii var. coreana, Tripterygium regelii ${\rightarrow}$Acer pseudo-sieboldianum var. koreanum, Betula costata, Quercus mongolica${\rightarrow}$Pinaceae forest(Pinus koraiensis, Abies koreana, Picea jezoznsis).