• Journal of Korean Neurosurgical Society
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• v.30 no.sup1
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• pp.44-50
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• 2001

Objectives : The objective of this study was to investigate the role of postoperative three dimensional short-range magnetic resonance angiography(3D-TOF MRA) in predicting the clinical outcomes following microvascular decompression(MVD) for the treatment of a hemifacial spasm(HFS). Material and Method : Postoperative magnetic resonance(MR) imaging was performed on 123 patients with a HFS between March 1999 and May 2000. All patients who had postoperative MR imaging were undertaken preoperative MR imaging. Of the 123 patients, 122 patients were included in this retrospective study. The degree of the detachment of vascular contact, and change of the position of offender were determined by pre- and postoperative 3D-TOF MRA. These findings were compared with the surgical findings and clinical outcomes. Results : Of 122 patients who had successful MVD, clear decompression of offenders of the root entry zone(REZ) of facial nerve was found in 106 patients(86.9%), partial decompression in 10 patients(8.2%) and contact of offenders to the REZ of facial nerve in 6 patients(4.9%) by the postoperative 3D-TOF MRA. Our patients demonstrated that the types of offender did not influence with the degree of decompression of REZ of facial nerve and with surgical outcomes(p>0.05). Also, there was no significant relationship between the degree of decompression of the REZ of facial nerve from offenders and an improvement of symptoms(p>0.05). Futhermore, there was no significant relationship between the degree of decompression of the REZ of facial nerve from offenders and an improvement time (p>0.05). Conclusion : Our data suggests that MVD of facial nerve alone may not be sufficient to resolve the symptoms in all patients with hemifacial spasm. Therefore, another unknown factors besides vascular compression may be involved to cause symptoms in certain patients and it may be necessary to remove these factors with MVD simultaneously to obtain the resolution of symptom.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.26 no.3
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• pp.250-257
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• 1993

The Global Positioning System(GPS) is a worldwide radio navigation system based on satellite technology. Signal availability and accuracy of GPS are subject to change due to an incomplete constellation and operational test activities. In order to analyze the signal availability and accuracy of GPS, we made an experiment on this system in Kunsan during April 6, 7, 9, 10, 1992. The results obtained are summarized as follows: 1. It was possible to avail the GPS system almost 24 hours per day, but sometimes it was impossible to obtain the GPS signal 2 or 3 times per day and its total time was at the most an hour. 2. By using satellite almanac, we also could calculate PDOP(HDOP) and forecast signal availability. And the mean positional error was $37.9{\sim}73.6m$ and standard deviation was $37.4{\sim}133.1m$. The positional error almost coincided with PDOP(HDOP). 3. The mean positional error of 3D was less than that of 2D. And the altitude error in 3D was about $56{\sim}74m$ and its standard deviation was about $65{\sim}93m$.

• Journal of the Korean earth science society
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• v.40 no.5
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• pp.502-517
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• 2019

Global warming and rapid climate change have long affected the characteristics of typhoons in the Northwest Pacific, which has induced increasing devastating disasters along the coastal regions of the Korean peninsula. Synthetic Aperature Radar (SAR), as one of the microwave sensors, makes it possible to produce high-resolution sea surface wind field around the typhoon under cloudy atmospheric conditions, which has been impossible to obtain the winds from satellite optical and infrared sensors. The Geophysical Model Functions (GMFs) for sea surface wind retrieval from SAR data requires the input of wind direction, which should be based on the accurate estimation of the center of the typhoon. This study estimated the typhoon centers using Sentinel-1A images to improve the problem of typhoon center detection method and to reflect it in retrieving the sea surface wind. The results were validated by comparing with the typhoon best track data provided by the Korea Meteorological Administration (KMA) and Japan Meteorological Agency (JMA), and also by using infrared images of Himawari-8 satellite. The initial center position of the typhoon was determined by using VH polarization, thereby reducing the possibility of error. The detected center showed a difference of 23.76 km on average with the best track data of the four typhoons provided by the KMA and JMA. Compared to the typhoon center estimated by Himawari-8 satellite, the results showed an average spatial variation of 11.80 km except one typhoon located near land with a large difference of 58.73 km. This result suggests that high-resolution SAR images can be used to estimate the center and retrieve sea surface wind around typhoons.

• Proceedings of the Ginseng society Conference
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• 2002.10a
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• pp.185-211
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• 2002

We have found many beneficial effects of the long-tenn intake of Korean red ginseng (KRG) in human immunodeficiency virus (HIV) type-I infected patients, including the maintenance of CD4+ T cell count for 10 years with KRG only and the delayed development of resistance mutation to ZDV. In this study, to investigate whether KRG-intake could affect the clinical progression and nef gene variation, we determined 200nef sequences from 70 patients. Follow-up period was $8.8{\pm}2.9$ years and annual decrease in CD4+T cell was $41{\pm}57/ul.$ Nested polymerase chain reaction (PCR) and direct sequencing were perfonned with peripheral blood mononuclear cells (PBMC) obtained at times during the study period. First, there was a significant correlation between survival duration and duration of KRG-intake $(36.8{\pm}38$ months)(P=0.000). There were significant correlations between the last NefProg score and CD4+ T cell count (r= 0.208, P<0.05) and annual decrease in CD4+ T cell count (r =0.346, P<0.01) in 70 patients. In addition, there were significant correlations between KRG-intake and annual decrease (r= 0.323, P<0.01), and the CD4+ T cell count itself (r=0.229, p<0.05). Furthennore, there was also a mild significance between the NefProg score and the duration of KRG-intake in only SP and RP (n=30, r=-0.281, P=0.067). In addition, we detected various defects in 21 patients $(30.0\%),$ not including 5 premature stop codons. Ten $(12.5\%)$ patients showed repeated deletion of an amino acid. Four of 10 patients were gross deletions and they were treated with KRG for more than 20 months. The number of patients with repeated gross deletions was significantly higher in the order of slow progressors $(18\%)$, typical progressors($3\%$), and rapid progressors($0\%$) (P<0.05). We also observed that long-tenn intake of KRG might make the change from A or D to T at position 54 and decrease NefProg score. Taken together, our results show clear evidence that the long-term intake of KRG has effects on nef gene variation as well as definite clinical usefulness.

• Journal of the korean academy of Pediatric Dentistry
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• v.48 no.2
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• pp.151-159
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• 2021

Since January 2019, insurance coverage for caries treatment of permanent teeth using composite resin in children aged 12 and under has started in South Korea. The purpose of this study was to compare the pattern of permanent molar composite resin restoration aged 12 and under before and after the insurance coverage from January 2009 to March 2020 in the Department of Pediatric Dentistry at Kyung Hee University Dental Hospital at Gangdong. Since the insurance coverage was started in 2019, the frequency of permanent molar composite resin restoration aged 12 and under has increased more than twice. There was a significant change in frequency of resin restoration by shape of cavity comparing before and after the insurance coverage, whereas there was no significant difference in changes by patient age, gender and position of tooth. As accessibility to the permanent tooth composite resin restoration is increased by the insurance coverage, which shows a fair survival rate, it is expected that it could be able to secure oral health in the early permanent dentition aged 12 and under.

• Journal of Korean Theatre Studies Association
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• no.48
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• pp.85-125
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• 2012

Geun Hyung Park is one of the playwrights who consistently pursues his unique world of play. One of the characteristics that is constantly discovered in Park's plays is the motif of 'family.' Park chooses family as the motif in most of his work. Park particularly emphasizes 'family life' rather than 'individual life' to focus on the internal problems of families. Therefore, the motif of family in Park's plays takes a very important position in the content and theme. The Korean society imposes unique value on families and possesses a strictly obstinate family ideology. Park observes distorted family relations or individuals who cannot be happy within their families to identify the problems related to the family ideology that is deeply rooted in the Korean society. This is one of the important backgrounds for which Park is constantly dealing with 'family life.' This study selected five of Park's most famous plays to specifically examine Park's critical understanding of family ideology. First, his criticizes extreme family egoism by depicting a family that cannibalizes people to keep the family full. Park chooses 'absurd time and space' and the extreme subject of 'human flesh' to warn his audiences about the awful consequences of family egoism. His , which is the only piece that deals with family history among the five pieces selected, criticizes Korea's unique family-centered ideology by humorously depicting the history of the Cho family that is all about maintaining and worshipping the its clan. He reveals the unethical and hypocritical attitudes of the Cho family for the audiences to reconsider the family-centered ideology of the Korean society. In , he talks about the son and the father who lose his ethical authority and fail to perform his paternal responsibilities to criticize the traditional family ideology of patriarchism and suggests the pessimistic future of patriarchism. contrasts a blood-related family with an irresponsible father and a quasi-family to criticize the identity of blood-related families. In , Park depicts a 'smelly house' of a family in agonizing relations to deny the family myth and the maternal myth. He clearly shows how the ideals of family myth and maternal myth are distant from the reality. In result of this study, Park's criticism of family ideology appears in various forms. He comprehensively criticizes both the general family problems and the unique family issues of Korea. The family ideology of Korea is currently undergoing a radical change. It has been long since the traditional family ideologies have exposed problems to show the signs of crisis. Also, there have emerged various forms of families, including single-parent families, one-person families, adoption families, and multi-cultural families. In this respect, Park's critical understanding of family ideologies allows you to see the obvious family forms from a new perspective and greatly contributes to awakening the essential questions about families. Park's work is noticeable among the various artistic and literature pieces that deal with family issues because of his extraordinary skills to capture the key issues inherent in the problems of family ideologies.

• Journal of Positioning, Navigation, and Timing
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• v.7 no.4
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• pp.295-305
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• 2018

Network RTK is a highly practical technology that can provide high positioning accuracy at levels between cm~dm regardless of user location in the network by extending the available range of RTK using reference station network. In particular, unlike other carrier-based positioning techniques such as PPP, users are able to acquire high-accuracy positions within a short initialization time of a few or tens of seconds, which increases its value as a future navigation system. However, corrections must be continuously received to maintain a high level of positioning accuracy, and when a time delay of more than 30 seconds occurs, the accuracy may be reduced to the code-based positioning level of meters. In case of SSR, which is currently in the process of standardization for PPP service, the corrections by each error source are transmitted in different transmission intervals, and the rate of change of each correction is transmitted together to compensate the time delay. Using these features of SSR correction is expected to reduce the performance degradation even if users do not receive the network RTK corrections for more than 30 seconds. In this paper, the simulation data were generated from 5 domestic reference stations in Gunwi, Yeongdoek, Daegu, Gimcheon, and Yecheon, and the network RTK and SSR corrections were generated for the corresponding data and applied to the simulation data from Cheongsong reference station, assumed as the user. As a result of the experiment assuming 30 seconds of missing data, the positioning performance compensating for time delay by SSR was analyzed to be horizontal RMS (about 5 cm) and vertical RMS (about 8 cm), and the 95% error was 8.7 cm horizontal and 1cm vertical. This is a significant amount when compared to the horizontal and vertical RMS of 0.3 cm and 0.6 cm, respectively, for Network RTK without time delay for the same data, but is considerably smaller compared to the 0.5 ~ 1 m accuracy level of DGPS or SBAS. Therefore, maintaining Network RTK mode using SSR rather than switching to code-based DGPS or SBAS mode due to failure to receive the network RTK corrections for 30 seconds is considered to be favorable in terms of maintaining position accuracy and recovering performance by quickly resolving the integer ambiguity when the communication channel is recovered.

• Korean Journal of Heritage: History & Science
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• v.45 no.4
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• pp.22-37
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• 2012

Storage facility of the pre-historic Korea is classified into the subterranean, ground and overground types. The rectangular-shaped subterranean Storage facilities have been identified in the Pungnaptoseong, the Gong mountain fortress site and the Gwanbukri site. Feature no. 196 at Gyeongdang District in Pungnaptoseong yielded a large quantity of glazed potteries, and a wooden storage at the Gwanbukri site contained a large amount of fruit seeds. These storage facilities might be functioned as the warehouse for the highest group rather than the storage for the emergency such as war and flooding and stipend of government officials. This article subdivided into "state storage" on the concept of the former that "royal storage" on the concept of the latter. If it look on the state storage at large, this include the royal storage too. But it subdivided to help article understand because Baekjae changed from state storage to royal storage by change and specialization of system after 4th. The reason why the diversification of storage pits was closely related to the unification of local polities and the concentration of political power in the state-level. Therefore, it might reflect the political circumstances the ruling elites attempted to heighten their authority in terms of the organizing tax collecting system. And divided the time of storage is confirmed separative storage pits in the suburbs of capital city. There is hight probability of top local polities or nation that have possessional a role. This is to cover on frequent war in the Three States. On the other hand, state storage is located around ancent road that linked castle gate that is divided into center and periphery depending on function and position of storage. Center is located royal storage focusing in the presumed royal palace that periphery is located state storage to provide service to the public. It is presumed that located with the government office.

• Journal of Navigation and Port Research
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• v.43 no.3
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• pp.172-178
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• 2019

Although the needs for providing resilient PNT information are increasing, threats due to the intentional RFI or space weather change are challenging to resolve. eLoran, which is a terrestrial navigation system that use a high-power signal is considered as a best back-up navigation system. Depending on the user's environment in the eLoran system, the user may use one of E-field or H-field antennas. H-field antenna, which has no restriction on setting stable ground and is relatively resistant to noise of general electronic equipment, is composed of two loops, and shows anisotropic gain pattern due to the different measurement at the two loops. Therefore, the H-field antenna's phase estimation value of signal varies depending on its direction even at the static environment. The error due to the direction of the signal should be eliminated if the user want to estimate the own position more precisely. In this paper, a method to compensate the error according to the geometric distribution between the H-field antenna and the transmitting station is proposed. A model was developed to compensate the directional error of H-field antenna based on the signal generated from the eLoran signal simulator. The model is then used to the survey measurement performed in the land area and verify its performance.

• Journal of Korean Tunnelling and Underground Space Association
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• v.21 no.5
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• pp.621-640
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• 2019

Quantitative stability assessment of underground cavities can be presented as a factor of safety based on the Shear Strength Reduction Method (SSRM). Also, SSRM is one of the stability evaluation methods commonly used in slope stability analysis. However, there is a lack of research that considers the relationship between the probability of occurrence of cavities in the ground and the potential failure surface of the slope at the same time. In this study, the effect of small underground cavities on the failure behavior of the slope was analyzed by using SSRM. Considering some of the glaciology studies, there is a case that suggests that there is a cavity effect inside the glacier in the condition that the glacier slides. In this study, the stability evaluation of underground cavities and slope stability analysis, where SSRM is used in geotechnical engineering field, was carried out considering simultaneous conditions. The slope stability analysis according to the shape and position change of underground cavities which are likely to occur in the lower part of a mountain road was analyzed by using SSRM in FLAC3D software and the influence of underground cavities on the slope factor of safety was confirmed. If there are underground cavities near slope potential failure surface, it will affect the calculation of a factor of safety. The results of this study are expected to be basic data on slope stability analysis with small underground cavities.