• Journal of the korean academy of Pediatric Dentistry
• /
• v.24 no.4
• /
• pp.788-794
• /
• 1997

As one of the developmental disturbance in shape of teeth, a twinning has very rare frequency in permanent teeth. Because it is possible to diagnose the twinning by use of the radiograph, it is very important to detect this anomaly early by careful examining the radiographs. The twinning produces several orthodontic problem such as crowding, protrusion, ectopic eruption of adjacent teeth. Therefore it is necessary, in proper time, the extraction and orthodontic treatment should perform.

• Proceedings of the KSRS Conference
• /
• 2003.11a
• /
• pp.1128-1130
• /
• 2003

This study investigated interannual variations in Northeastern Asian vegetation activity inferred from NOAA/AVHRR data during 1984 to 1993. Firstly, original NOAA/AVHRR data was radiometrically and atmospherically corrected in order to produce a consistent and calibrated time series NDVI by eliminating the effect of atmospheric effects and sensor degradation. Next, the NDVI data was analyzed to detect terrestrial ecosystem responses to climate change. A larger increase in growing season NDVI magnitude was observed in Northeastern Asia. Especially, vegetation activity is increasing in north part of Northeastern Asia. However, satellite drift and eruption effect have affect on interannual NDVI variations and it has affected the result in some degree. To improve accuracy of the result, it is necessary to correct these effects.

• Journal of International Area Studies (JIAS)
• /
• v.18 no.3
• /
• pp.109-144
• /
• 2014

In 2010, large areas of European airspace were closed by the volcanic ash generated by the eruption of Icelandic volcano and it disrupted global trade, business and travel which caused a huge economic damage on the air transport industry. This brought concerned about the economic impact by the eruption of Mt. Baekdu volcano. In this paper, we analyze the affected areas of the air transport industry were decided by calculating the PM10 density of volcanic ash changed over time and by determining the safe upper limit of ash density in their airspace. We separate the sales in the air transport industry according to each airline, airport, and month to estimate the direct losses when all flights inside a restricted zone were canceled. Also, we estimate the indirect losses in regional output, income, and value-added of the different major industries using interindustry (input-output) analysis. There is no direct damage from VEI 1 to VEI 5. But when VEI is 6, all flights to and from Yangyang airport will be canceled due to the No Fly Zone. And some flights to and from the airports Gimhae, Ulsan and Pohang will be restricted due to the Time Limited Zone. When VEI is 7, Yangyang, Gimhae, Ulsan, Pohang and Daegu airports will be closed and all flights will be canceled and delayed. During this time, the total economic losses on the air transport industry are estimated at 8.1 billion won(direct losses of about 3.55 billion won, indirect losses of about 4.57 billion won). Gimhae international airport accounted for 92% of the total loss and is the most affected area according to the volcanic ash scenario of Mt. Baekdu.

• The Bulletin of The Korean Astronomical Society
• /
• v.43 no.1
• /
• pp.53.1-53.1
• /
• 2018

During a major solar eruption, the erupting plasma is possibly out of the equilibrium ionization state because of its rapid heating or cooling. The non-equilibrium ionization process is important in a rapidly evolving system where the thermodynamical time scale is shorter than the ionization or recombination time scales. We investigate the effects of non-equilibrium ionization on EUV and X-ray observations by the Atmospheric Imaging Assembly (AIA) on board Solar Dynamic Observatory and X-ray Telescope (XRT) on board Hinode. For the investigation, first, we find the emissivities for all the lines of ions of elements using CHIANTI 8.07, and then we find the temperature responses multiplying the emissivities by the effective area for each AIA and XRT passband. Second, we obtain the ion fractions using a time-dependent ionization model (Shen et al. 2015), which uses an eigenvalue method, for all the lines of ion, as a function of temperature, and a characteristic time scale, $n_et$, where $n_e$ and t are density and time, respectively. Lastly, the ion fractions are multiplied to the temperature response for each passband, which results in a 2D grid for each combination of temperature and the characteristic time scale. This is the set of passband responses for plasma that is rapidly ionized in a current sheet or a shock. We investigate an observed event which has a relatively large uncertainty in an analysis using a differential emission measure method assuming equilibrium ionization state. We verify whether the observed coronal plasmas are in non-equilibrium or equilibrium ionization state using the passband responses.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.35 no.4
• /
• pp.766-770
• /
• 2008

Gingival fibromatosis is a rare condition characterized by varying degrees of gingival hyperplasia. Gingival fibromatosis usually occurs as an isolated disorder or can be associated with a variety of other syndromes. It usually appears at the time of eruption of permanent dentition but, can develop at the time of eruption of the primary dentition and rarely at birth. It may deform palatal contour and subsequently restrict the tongue movement, resulting in interference during speech and mastication. In addition, it incapacitates maintenance of normal lip closure. A 14-month-old girl visited the department of pediatric dentistry, Yonsei University Dental Hospital, for the congenital gingival overgrowth. There was no one in the family, who showed similar pattern of gingival growth. The intraoral clinical examination revealed generalized severe gingival enlargement throughout the maxillary and the mandibular arches. Enlarged gingival tissue was pink and had firm consistency. She was referred for chromosomal analysis, which confirmed absence of any known syndrome. Under local anesthesia, "Punch-biopsy" was performed on the labial area, and the specimen was histologically diagnosed as gingival fibromatosis. For she did not have any medical problem nor familiar history, she was diagnosed as having idiopathic gingival fibromatosis. Regarding her age and behavior, close follow-up was decided.

• The Journal of the Petrological Society of Korea
• /
• v.22 no.1
• /
• pp.35-47
• /
• 2013

The Baegdusan Volcano which erupted violently at 1000 AD is still have possibility of eruption. Therefore, it is necessary to monitor regularly the possibility of eruption. However, it is very difficult to install regular monitoring system or to get regularly monitored data due to geopolitic problems. This is why we have to develop regular monitoring technique using satellite. The geoid in the Baegdusan Volcanic area calculated from gravity data obtained from GRACE satellite, decreased from 2002 to 2005. The period of decreasing is well matched with time when magma activities were recognized in the Baegdusan Volcanic area. The decrease in geoid is interpreted to be caused by the decrease of water storage. Considering that the amount of rainfall from 2002 and 2005 is almost constant, the decrease in geoid may be related to the magma activity under the Baegdusan Volcano. The geomagnetic total force in the Baegdusan Volcanic area measured by CHAMP satellite, decreased from 2000 to 2005 and increased after 2005. The period of decrease is well matched with the time with increased activity of magma chamber under the Baegdusan Volcano indicating that the decrease of geomagnetic total force is caused by demagnetization of surrounding rocks due to the increase of temperature of magma chamber. These data indicate the possbility of using change of geoid and geomagnetic total force observed by GRACE and CHAMP satellites for the monitoring of magma activity under the Baegdusan Volcano.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.35 no.4
• /
• pp.750-756
• /
• 2008

Supernumerary teeth are frequently found in the anterior portion of the maxilla and develop as a result of abnormal proliferation of the dental lamina during tooth germ formation, caused by genetic or environmental factors. They may result in various complications, such as eruption interference, displacement, rotation of adjacent teeth, diastema, eruption into the nasal cavity, and development of dentigerous cyst. The optimal time for surgical extraction of supernumerary teeth has been a controversial issue. Someone prefer early surgical extraction because supernumerary teeth can cause eruption interference and displacement of adjacent teeth, eventually altering occlusion. Others prefer to delay surgical extraction until $8{\sim}10$ years of age in consideration of root maturation of the adjacent teeth and also patient's behavior. When surgical extraction of supernumerary teeth is postponed, there is possibility that impacted supernumerary teeth in the inverted or horizontal position move toward the nasal cavity, hard palate, or premolar area. When such intraosseous tooth migration is combined with the vertical growth of the maxilla, surgical approach becomes even harder. Therefore, possibility of intraosseous tooth migration should be considered as an important factor when deciding appropriate time for surgical extraction. We are presenting cases of mesiodens which showed intraosseous migration during $6{\sim}7$ years of follow-up period since the first diagnosis had been made at the $2{\sim}3$ years of age.

• Journal of The Korean Astronomical Society
• /
• v.36 no.spc1
• /
• pp.37-44
• /
• 2003

In this paper, we review recent studies on the magnetic helicity changes of solar active regions by photospheric horizontal motions. Recently, Chae(200l) developed a methodology to determine the magnetic helicity change rate via photospheric horizontal motions. We have applied this methodology to four cases: (1) NOAA AR 8100 which has a series of homologous X-ray flares, (2) three active regions which have four eruptive major X-ray flares, (3) NOAA AR 9236 which has three eruptive X-class flares, and (4) NOAA AR 8668 in which a large filament was under formation. As a result, we have found several interesting results. First, the rate of magnetic helicity injection strongly depends on an active region and its evolution. Its mean rate ranges from 4 to $17 {\times} 10^{40}\;Mx^2\;h^{-1}$. Especially when the homologous flares occurred and when the filament was formed, significant rates of magnetic helicity were continuously deposited in the corona via photospheric shear flows. Second, there is a strong positive correlation between the magnetic helicity accumulated during the flaring time interval of the homologous flares in AR 8100 and the GOES X-ray flux integrated over the flaring time. This indicates that the occurrence of a series of homologous flares is physically related to the accumulation of magnetic helicity in the corona by photospheric shearing motions. Third, impulsive helicity variations took place near the flaring times of some strong flares. These impulsive variations whose time scales are less than one hour are attributed to localized velocity kernels around the polarity inversion line. Fourth, considering the filament eruption associated with an X1.8 flare started about 10 minutes before the impulsive variation of the helicity change rate, we suggest that the impulsive helicity variation is not a cause of the eruptive solar flare but its result. Finally, we discuss the physical implications on these results and our future plans.

• Journal of KIISE
• /
• v.42 no.3
• /
• pp.281-288
• /
• 2015

A volcano disaster damage prediction system supports decision making for counteracting volcanic disasters by simulating meteorological condition and volcanic eruptions. In this system, a program called Fall3D generates predicted results for the diffusion of ash after a volcanic eruption on the basis of meteorological information. The relevant meteorological information is generated by a weather numerical prediction model known as Weather Research & Forecasting (WRF). In order to reduce the entire processing time without modifying these two simulation programs, pipelining can be used by partly executing Fall3D whenever the hourly (partial) results of WRF are generated. To reduce the processing time, successor programs such as Fall3D require that certain features be suspended until the part of the results that is based on prior calculation is generated by a predecessor. Even though Fall3D does not have a suspend or resume feature, pipelining effect can be produced by using the program's restart feature, which resumes simulation from the previous session. In this study, we suggest a workflow that can control the execution type.

• Journal of the Korean Applied Science and Technology
• /
• v.19 no.1
• /
• pp.19-24
• /
• 2002

It is a great role that the character of man or woman could be distinguished by hair on the aspect of ornament. Hair will be support of beautifulness of human being in various permanent wave by many kinds of its drugs. Hair is based upon the skin which enroll the body of high living animals and have multiple membrane structure. This study used rat and the effects of commercial permanent wave products to skin which are composed with thioglycolic acid and bases. Results are as follows. Permanent wave penetrated to 4 hours later with steady state in skins and was not significant changeable after 20hr later. In case of neutralizer with thioglycolic acid lag time and permeability coefficient in healthy skin is 3.38hr and $0.094^{\mu}g/cm^{2}$ ${\cdot}$ hr, it old skin is 3.48hr and 0.129$^{\mu}g/cm^{2}$ ${\cdot}$ hr, and it wounded skin is 4.72hr and $0.158^{\mu}g/cm^{2}$ ${\cdot}$ hr. In conclusion, lag time and permeability coefficient in old skin and wounded skin are faster than healthy skin. In vivo which was studied by general time and method of permanent wave. We notified that fine rinkle and rash of skin were changeable in the case of treating with permanent wave drugs than normal skin. We can see even rash and eruption by the naked eye.