• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2004.04a
• /
• pp.408-412
• /
• 2004

A total of 23 springs distributed in the southern and northern sides of Mt. Hala in Jeju Island were seasonally sampled and analyzed for their major ion chemistry and oxygen and hydrogen isotope compositions to investigate their hydrogeochemical and isotopic characteristics. Dissolved ion concentrations of the south-side springs slightly increase with decreasing altitude. This indicates that dissolved ion concentrations of groundwater recharged at higher altitudes increase by water-rock interaction during the downgradient migration of groundwater through highly permeable volcanic aquifer. Dissolved ion concentrations of the north-side springs also slightly increase with decreasing altitude, but dramatically increase at ～300 m.a.s.l. This may indicate a sudden input of contaminants to the north-side groundwater system around ～300 m.a.s.l. Springs located in areas above ～300 m.a.s.l. have very low concentrations of dissolved ions, showing little seasonal variations. Whereas springs located in areas below ～300 m.a.s.l. show a big seasonal variation in the concentration of dissolved ions. Seasonal variation of oxygen isotope compositions of springs is ～3$\textperthousand$ for high-altitude springs (～1700 m.a.s.l.) and is ～2$\textperthousand$ near shore, indicating an attenuation of the variation through mixing with other groundwater bodies during migration.

• Journal of Integrative Natural Science
• /
• v.8 no.3
• /
• pp.221-232
• /
• 2015

In this study, the vertical characteristics of wind were analyzed using the horizontal wind, vertical wind, and vertical wind shear, which are generated from a wind profiler during concentrated heavy rain, and the quantitative characteristics of concentrated heavy rain were analyzed using CAPE, SWEAT, and SRH, among the stability indexes. The analysis of the horizontal wind showed that 9 cases out of 10 had a low level jet of 25 kts at altitudes lower than 1.5 km, and that the precipitation varied according to the altitude and distribution of the low-level jet. The analysis of the vertical wind showed that it ascended up to about 3 km before precipitation. The analysis of the vertical wind shear showed that it increased up to a 1 km altitude before precipitation and had a strong value near 3 km during heavy rains. In the stability index analysis, CAPE, which represents thermal buoyancy, and SRH, which represents dynamic vorticity, were used for the interpretation of the period of heavy rain. As SWEAT contains dynamic upper level wind and thermal energy, it had a high correlation coefficient with concentrated-heavy-rain analysis. Through the case studies conducted on August 12-13, 2012, it was confirmed that the interpretation of the prediction of the period of heavy rain was possible when using the intensive observation data from a wind profiler and the stability index.

• Journal of Korean Academy of Nursing
• /
• v.6 no.1
• /
• pp.1-11
• /
• 1976

In an attempt to recognize attitudes of teachers and general public toward mental health, III teachers of middle and high school and 130 general public were selected for this study from September 6, 1975 to October 18, 1975. Date were collected through "Mental Health Questionnaire"designed by Nounally. Results of the study were as follows : 1. The selected teacher group and general public group revealed almost similar altitudes toward psychotic patients, that is, positive aspects for employment problems and relationship toward other persons. 2. Both teacher group and general public group revealed the same attitudes toward neurotic patients, felt relatively more reliance on them, and showed much more positive attitudes toward neurotic patients than psychotic patients. 3. Both groups indicated that, for the security of mental health, It is best way to show him the right path and make sure that he follows it. As to mental health, most of the selective subjects consulted with psychiatrist about the problems and obtained the information through books. 4. Both teacher group and general public group identified mental illness being equal in seriousness to alcoholism or cardiac disease. In case of a close relative living in their home having mental disease, most of them responded to be glad to help him. 5. Both teacher group and general public group revealed intensively negative attitudes toward mental hospital in order of despair. danger, and filth, while positive attitudes toward psychiatrist.

• The Korean Journal of Ecology
• /
• v.18 no.3
• /
• pp.353-366
• /
• 1995

To study the relationship between the germination response and geographical distribution, the seeds of Rumex acetocella were collected from nine sites (Taegwallyong, Alps lodge, Kans'ong, Sokch'o, Chumunjin, Suwon, Taechon, Sukgok, Mokpo) of different latitudes and altitudes. The populations of Rumex acetocella were subdivided into four groups based on the characteristics of the seed germination. The first group of Rumex acetocella (Taegwallyong, Alps lodge) germinated rapidly in early spring, the second group (Suwon, Teachon) in late summer through early autumn, and the third group(Sukgok, Mokpo) slowly in late autuman with various conditions. The thermal time values needed for the germination rate of 10% to 60% for these three groups indicated that the germination rate was low at the lower latitude, while it was increased as the latitude elevated. The population of the fouth group (Kansong, Sokcho, Chumunjin) showed the narrow optimum temperature range of germination response and the highest thermal time value to germinate 10% to 30% of seeds. The seeds in the high latitude region with relatively mild winter germinated synchronously in early autumn. These different germination responses of Rumex acetocella to geographic variations were thought to be an ecological strategy to survive in different environmental conditions.

• Journal of Ecology and Environment
• /
• v.32 no.4
• /
• pp.249-256
• /
• 2009

The rare endemic plant, Smilax wightii, is generally distributed in shola forests at high altitudes in Nilgiri Biosphere Reserve, the Western Ghats, southern India. To determine the ecological status of the species, we surveyed 11 major shola forests in that region. S. wightii has a limited distribution in all sholas (frequency value of < 13%). The density of the species is generally around $15/100\;m^2$ in the sholas except in Thiashola where it occurred at a density of 40 individuals/$100\;m^2$. The density of S. wightii was generally greater in the margins of the shoals, while the interior forests contained fewer individuals per unit area. The basal cover occupied by this species ranged between 2246 and $3144\;mm^2/100\;m^2$. The importance value index for S. wightii was >2 in all shoals, which indicates that the species occupies an important position in the lower stratum of shola forests of Nilgiri Biosphere Reserve.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.19 no.4
• /
• pp.342-348
• /
• 2014

In this paper, a BLDC(Brushless DC) motor control system for driving fins to control the flight attitude of the guided artillery munition is developed. This system adopts a sensorless control scheme without any position sensor such as a Hall sensor fragile at high altitudes. The sensorless control of the BLDC motor is achieved by using commutation signals obtained from the measured pole voltages. The position control of the fin is also performed by using of the estimated speed from the commutation signals. The experimental results on the actual fin drive system demonstrated that the developed sensorless control algorithm can give an excellent position control performance.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.10 no.3
• /
• pp.137-140
• /
• 1990

This study was carried out to investigate the effects of slope exposure and altitude on the dry matter yield and on the grass quality in mountain pasture for 2-year period from 1986 to 1987. 1. Dry matter yield and crude protein content of grasses by slope exposure in mountain pasture were higher on the northern slope than that on the southern slope and, on both sides of slope, were increased as the altitude was high. 2. Neutral detergent fiber(NDF) and acid detergent fiber(ADF) contents, and in vitro dry matter digestibility were not different between different slope exposures and between different altitudes.

• Asian Journal of Turfgrass Science
• /
• v.10 no.1
• /
• pp.71-80
• /
• 1996

Fourteen dictyostelids(12 species of genus Dictyostelium. 2 species of genus Polysphonylium) oc-curred in Mt. Chiri Korea. Soils samples were collected from the nine sites. In the broadleaved-deciduous forests and conifers, common species of cellular slime molds are Dictyostelium mucoroides, and D. brefeldianum. Only two species are above 30 in importance value and above 50% in presence. Dominant species in the broadleaved-deciduous forests is D. mecoroides wheras in the conifer forests is D. brefeldianum which was not common until now in Korea, found in the low elevation either. In addition, Five cellular slime molds occured in the Miscanthus sinensis community: 4 species of genus Dictyostelium and 1 species of genus Polysphonylium. Dominant species is D. purpureum. Importance value is very high, 85. This Result is exceptively unusual. It dind't occur in the other sites. Correlation between the altitudes and the occurrence and distribution of dictyostelids was not accurate. Merely dominant species were different according to forest types and organic matter contents in soil. Cellular slime molds have different favorite forest types. And the growth and germination are dependent on the soil enviroryrnental conditions and soil quility. Key words:Dictyostelids, Mt. Chiri D. mecoroides, D. brefeldianum. D. purpureum. Soil quility, Favorite forest type, Soil environmental condition.

• Journal of Astronomy and Space Sciences
• /
• v.36 no.3
• /
• pp.213-223
• /
• 2019

This paper analyzes delta-Vs to maintain an extremely low altitude on the Moon and investigates the possibilities of performing a CubeSat mission. To formulate the station-keeping (SK) problem at an extremely low altitude, current work has utilized real-flight performance proven software, the Systems Tool Kit Astrogator by Analytical Graphics Inc. With a high-fidelity force model, properties of SK maneuver delta-Vs to maintain an extremely low altitude are successfully derived with respect to different sets of reference orbits; of different altitudes as well as deadband limits. The effect of the degree and order selection of lunar gravitational harmonics on the overall SK maneuver strategy is also analyzed. Based on the derived SK maneuver delta-V costs, the possibilities of performing a CubeSat mission are analyzed with the expected mission lifetime by applying the current flight-proven miniaturized propulsion system performances. Moreover, the lunar surface coverage as well as the orbital characteristics of a candidate reference orbit are discussed. As a result, it is concluded that an approximately 15-kg class CubeSat could maintain an orbit (30-50 km reference altitude having ${\pm}10km$ deadband limits) around the Moon for 1-6 months and provide almost full coverage of the lunar surface.

• Journal of the Korean Society for Aviation and Aeronautics
• /
• v.30 no.2
• /
• pp.44-54
• /
• 2022

An empirical analysis was conducted on the workload of helicopter pilots flying in high-risk flight environments such as ground obstacles and weather effects at low altitudes. To evaluate the workload, an independent sample t-test was performed using the NASA-TLX evaluation method most suitable for the aviation field, and the workload score was calculated by applying the analytical stratification method (AHP) to compare and analyze private and commercial pilots. There is a significant difference in mean between private and commercial pilots and the result of work load was obtained over 70%. This paper studied the 'surprise and startle effect' on the helicopter field for the first time. In the future, it is intended to contribute to the safe operation of helicopters by presenting a method for effective safety management by utilizing it in the field of education and training for helicopter pilots and providing basic data for preventing accidents caused by human error.