• The Bulletin of The Korean Astronomical Society
• /
• v.37 no.2
• /
• pp.116.2-116.2
• /
• 2012

The structure of plasmasphere plays an important role in determining properties of geomagnetic ULF pulsations such as Pi 2 pulsations and field line resonances (FLRs) in the Earth's magnetosphere. We have performed a 3-D MHD wave simulation to investigate the generation and propagation of ULF waves in dipole geometry. Various 3-D density structures are assumed, which include a relatively sharp density gradient and gradually less slopes at the plasmapause. The former condition can refer to the plasmasphere from local midnight to dawn, whereas the latter represents the region near noon to dusk where it bulges out. We show how Pi 2 pulsations and FLRs differentially appear at both multi-point satellite locations and ground stations for different local times. Our results suggest that 1) the local radial density structure significantly affects the peak frequencies for Pi 2 oscillations, while the polarization changes remain similar in the radial direction, and 2) the radial location of strong FLRs varies for different density profiles. It is also suggested how multi satellite measurements and ground-based observations can confirm this differential feature in space.

• Journal of IKEEE
• /
• v.23 no.1
• /
• pp.173-180
• /
• 2019

There is a case where the output of renewable energy(RE) is curtailed due to an increase in the share of RE. Typically, wind power(WP) is curtailed due to oversupply and low load at midnight. However there is a case where the output of WP is limited during daytime due to the increase in share of photovoltaic(PV). In current electricity market, as the share of PV is increased, the curtailments of WP will be increased further, which will add to the difficulties of wind farm operators. In this paper, we propose a method to distribute the power limit of RE according to the criterion based on the priority constraint of the energy source which is difficult to operate the power system.

• Journal of Positioning, Navigation, and Timing
• /
• v.12 no.4
• /
• pp.423-430
• /
• 2023

One recent notable method for real-time elimination of ionospheric errors in geodetic applications is the Predicted Global Ionosphere Map (PGIM). This study analyzes the level of accuracy achievable when applying the PGIM provided by the Center for Orbit Determination of Europe (CODE) to the Korean Peninsula region. First, an examination of the types and lead times of PGIMs provided by the International GNSS Service (IGS) Analysis Center revealed that CODE's two-day prediction model, C2PG, is available approximately eight hours before midnight. This suggests higher real-time usability compared to the one-day prediction model, C1PG. When evaluating the accuracy of PGIM by assuming the final output of the Global Ionosphere Map (GIM) as a reference, it was found that on days with low solar activity, the error is within ~2 TECU, and on days with high solar activity, the error reaches ~3 TECU. A comparison of the errors introduced when using PGIM and three solar activity indices-Kp index, F10.7, and sunspot number-revealed that F10.7 exhibits a relatively high correlation coefficient compared to Kp-index and sunspot number, confirming the effectiveness of the prediction model.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.29 no.11
• /
• pp.605-611
• /
• 2017

The purpose of this study is to calculate the energy consumption rate based on data regarding energy use in office buildings, and to confirm the general characteristics of energy consumption. The energy consumption rate of the building is calculated by dividing the energy consumption by the floor area. The energy consumption rate of small-sized office buildings was calculated as $101.48{\sim}201.55kWh/m^2{\cdot}year$ and in the case of medium-sized buildings, the range was $92.77{\sim}177.89kWh/m^2{\cdot}year$. In the case of small buildings, it was found that the energy consumption was $73.24kWh/m^2{\cdot}year$ in electronic device, $34.31kWh/m^2{\cdot}year$ in hot water supply, and $18.37kWh/m^2{\cdot}year$ in heating. In the case of medium-sized buildings, electronic devices was $73.08kWh/m^2{\cdot}year$, lighting was $18.35kWh/m^2{\cdot}year$ and heating, $15.37kWh/m^2{\cdot}year$. In all of the study buildings, the peak heating energy use was observed from 8:00 a.m. to 10:00 a.m during the winter, and the peak power management was required. Energy use at and around the midnight hour is confirmed to be 40~60% of weekly working hours, so it is necessary to manage power use at night time as well as during the day. In order to improve the accuracy of future studies, it is necessary to make efforts to secure the data with standardized energy measuring units for the various type of buildings.

• The Korean Journal of Food And Nutrition
• /
• v.28 no.5
• /
• pp.782-793
• /
• 2015

The purpose of this study is the examination of stress levels and the eating habits that are affected by stress, and the provision of basic nutritional education data for the improvement of the eating habits of students who have experienced stress-related nutritional problems. Using the BEPSI-K instruments, a questionnaire survey was administered to 327 student subjects (166 male and 161 female) in the areas of Seoul and Gangwon province. The subjects were classified into 3 groups (low-stress, medium-stress and high-stress), and 59 students (18%) belonged the high-stress group. The BMI readings of the Gangwon province students are significantly higher than those of the Seoul students. The survey results show that the lunch frequency and vegetable intake levels are lower in the high-stress group, whereas the intakes of hot spicy food is higher in this group; they also show that Gangwon province students had eating habits that are relatively undesirable compared with the Seoul students. There are significant differences between the Seoul students and Gangwon porvince students regarding residence type, household economic level, types of leisure activities and level of some stresses. The Gangwon province students ate occasionally breakfast, lunch and snacks, but their midnight snack consumption is relatively frequent compared with the Seoul students. The results of the survey indicate that the BEPSI-K score has a negative correlation with the following variables : sleeping time, economic level of household, degrees of satisfaction regarding appearance and academic achievements, lunch frequency and vegetable intakes. Desirable eating habits are essential for the maintenance of a favorable health status and for the stress-management of university students who need to be a healthy members of society in the near future. To facilitate the formation of desirable eating habits among university students, community-based nutritional assistance and appropriate nutritional education programs should be considered necessary.

• Journal of The Korean Society of Clinical Toxicology
• /
• v.2 no.2
• /
• pp.90-95
• /
• 2004

Purpose: The purpose of this study is to compare the toxicologic characteristics of two groups of patients with acute intoxication for two different time periods and to make recommendations based on the results of this study. Methods: We reviewed retrospectively the medical records of patients with acute intoxication in our emergency center from June 1997 to May 1998 (group A) and from June 2000 to May 2003 (group B), and we evaluated differences in the epidemiologic and the toxicologic characteristics between the two groups. Results: The ratios of the number of patients with acute intoxication to the total numbers of patients who visited our emergency department were $0.49\%$ and $0.52\%$ for groups A and B, respectively. In both groups many poisoned patients visited our emergency center from 4:00 pm to midnight. The interval between the time of intoxication and arrival at the hospital was significantly shorter in group B. The number of patients transferred to our emergency center was larger in group B. Attempted suicide was the major cause of acute intoxication in both groups. Major toxic substances in both groups were centrally active drugs and insecticides. The number of comatose and mechanically ventilated patients was larger in group B. However, there was no statistically significant difference in the mortality rates. Conclusion: Emergency physicians who manage intoxicated patients should recognize regional characteristics and differences in the toxicologic characteristics of poisoning. In addition, the establishment of a poisoning control center in the regional emergency center is necessary to integrate data control and to enhance specialized management of intoxicated patients.

• Bulletin of the Korean Space Science Society
• /
• 2011.04a
• /
• pp.26.3-27
• /
• 2011

Formation of a steep plasma density gradient in the middle-latitude ionosphere during geomagnetic storms and the latitudinal migration of its location depending on the storm phase are suggested to be associated with the ionospheric signature of the plasmapause. We test this idea by using the satellite and ground observation data during the 11 April 2001 storm. The locations of the steep plasma density gradient identified by TOPEX/Poseidon (2001 LT) and DMSP (1800 and 2130 LT) satellites coincide with the ionospheric footprints of the plasmapause identified by the IMAGE satellite. This observation may support the dependence of the middle-latitude plasma density gradient location on the plasmapause motion, but does not explain why the steep density gradient whose morphology is largely different from the morphology of the middle-latitude ionization trough during quiet period is formed in association with the plasmapause. The ionospheric disturbances in the total electron content (TEC) maps shows that the steep TEC gradient is formed at the boundary of the positive ionospheric storm in low-middle latitudes and the negative ionospheric storm in middle-high latitudes. We interpret that the thermospheric neutral composition disturbance in the dayside is confined within the middle-high latitude ionospheric convection zone. The neutral composition latitudes and, therefore, the locations of the steep plasma density gradient coincide with the footprints of the plasmapause. The TEC maps show that the appearance of the steep plasma density gradient in the pre-midnight sector during the recovery phase is related to the co-rotation of the gradient that is created during the main phase.

• The Journal of Korean Medicine
• /
• v.28 no.3 s.71
• /
• pp.197-206
• /
• 2007

Objectives : By recording basic data of patients visiting the emergency room of the oriental medicine center, we can understand their characteristics and gain better insight about them. Methods : We performed a retrospective study of 2,674 patients who visited the emergency room of Kyunghee Oriental Medical Center, from June 1, 2006 to May 31, 2007. Results : 1. Of 2,674 total patients, the male to female ratio was 0.94:1 and the 6th decade of life was the peak age group. 2. The majority of patients visited our emergency room between 06:00 and 24:00(midnight). 3. Most patients visited on a Saturday or Sunday. 4. By monthly distribution, the patients increased slightly during June, July, August and October. 5. The majority of patients visited the emergency room within 24 hours of onset. 6. The patients were categorized as follows: neurological diseases 71.15%, musculoskeletal diseases 16.02%, internal medical disease 9.04%, psychiatric and related disease 3.79%. 7. The average transit time was about 1 hour 30 minutes. 8. Admission rate was 48% and the rate of admission to the intensive care unit (ICU) was 5% of total visiting patients. Conclusion : Assuming that this research will continue adding patient's data continuously, this work will help us to understand the features of patients who visiting the emergency room of the oriental medical center.

• Journal of Korean Society of Transportation
• /
• v.34 no.5
• /
• pp.394-408
• /
• 2016

This study aims to study the impact of weather conditions and locational characteristics of bike stations on the usage of public bike sharing system for efficient deployment and operation of public bike systems. Linear regression analysis is used to estimate the usage of public bikes of Goyang city. The statistical analysis shows that the usage rate increases with average temperature and decreases under high wind (over 7m/s) or high temperature (over $29^{\circ}$) condition. The usage rate of public bike sharing system can be differentiated by locational characteristics of bike station such as residential area, commercial area, park, school, and metro station. The usage rate increases in park and commercial areas from 10 AM to 3 PM, while it increases in school areas from 3 PM to 5 PM. Public bikes are highly used near the metro station from 5 PM to 8 PM. The stations in parks are highly used in late night, and the usage rate in CBD area increases after the midnight.

• Journal of Astronomy and Space Sciences
• /
• v.21 no.4
• /
• pp.303-314
• /
• 2004

In this paper we report some properties of inner magnetospheric structure inferred from the T01_s code, one of the latest magnetospheric models by Tsyganenko. We have constructed three average storms representing moderate, strong, and severe intensity storms using 95 actual storms. The three storms are then modelled by the T01_s code to examine differences in magnetic structure among them. We find that the magnetic structure of intense storms is strikingly different from the normal structure. First, when the storm intensity is large, the field lines anchored at dayside longitudinal sectors become warped tailward to align to the solar wind direction. This is particularly so for the field lines anchored at the longitudinal sectors from postnoon through dusk. Also while for the moderate storm the equatorial magnetic field near geosynchronous altitude is found to be weakest near midnight sector, this depression region expands into even late afternoon sector during the severe storm. Accordingly the field line curvature radius at the equator in the premidnight geosynchronous region becomes unusually small, reaching down to a value less than 500 km. We attribute this strong depression and the dawn-dusk asymmetry to the combined effect from the enhanced tail current and the westward expansion/rotation of the partial ring current.