• 소성∙가공
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• 제8권3호
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• pp.276-283
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• 1999

This study focuses on part quality and cycle times under gas-assisted injection molding (GIM) of box shape molded parts. The position of the gas channel was established near to parting line at the end of last locations to fill. Applied hot runner and valve gates, the gas was introduced directly into the mold cavity via gas pin. As GIM was applied, the conclusion reached as follows. I) The quality of appearance was improved by reducing sink marks and scratches of texture. ii) The reliability was improved by preventing warpages and reinforcing rigidity through optimum gas channel layout. iii) It is enable to use small size of injection molding machine step by step as GIM was accomplished low pressure and reduced clamp forces against CIM. iv) The productivity were improved by reducing cycle times.

• Journal of Positioning, Navigation, and Timing
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• 제12권4호
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• pp.343-348
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• 2023

The ionosphere acts as the largest error source in the Global Navigation Satellite System (GNSS) signal transmission. Ionospheric total electron content (TEC) is also easily affected by changes in the space environment, such as solar activity and geomagnetic storms. In this study, we analyze changes in the regional ionosphere using the Qusai-Zenith Satellite System (QZSS), a regional satellite navigation system. Observations from 9 GNSS stations in South Korea are used for estimating the QZSS TEC. In addition, the performance of QZSS TEC is analyzed with observations from day of year (DOY) 199 to 206, 2023. To verify the performance of our results, we compare the estimated QZSS TEC and CODE Global Ionosphere Map (GIM) at the same location. Our results are in good agreement with the GIM product provided by the CODE over this period, with an averaged difference of approximately 0.1 TECU and a root mean square (RMS) value of 2.89 TECU.

• Journal of Positioning, Navigation, and Timing
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• 제6권3호
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• pp.125-133
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• 2017

Time comparison is necessary for the verification and synchronization of the clock. Two-way satellite time and frequency (TWSTFT) is a method for time comparison over long distances. This method includes errors such as atmospheric effects, satellite motion, and environmental conditions. Ionospheric delay is one of the significant time comparison error in case of the carrier-phase TWSTFT (TWCP). Global Ionosphere Map (GIM) from Center for Orbit Determination in Europe (CODE) is used to compare with Bernese. Thin shell model of the ionosphere is used for the calculation of the Ionosphere Pierce Point (IPP) between stations and a GEO satellite. Korea Research Institute of Standards and Science (KRISS) and Koganei (KGNI) stations are used, and the analysis is conducted at 29 January 2017. Vertical Total Electron Content (VTEC) which is generated by Bernese at the latitude and longitude of the receiver by processing a Receiver Independent Exchange (RINEX) observation file that is generated from the receiver has demonstrated adequacy by showing similar variation trends with the CODE GIM. Bernese also has showed the capability to produce high resolution IONosphere map EXchange (IONEX) data compared to the CODE GIM. At each station IPP, VTEC difference in two stations showed absolute maximum 3.3 and 2.3 Total Electron Content Unit (TECU) in Bernese and GIM, respectively. The ionospheric delay of the TWCP has showed maximum 5.69 and 2.54 ps from Bernese and CODE GIM, respectively. Bernese could correct up to 6.29 ps in ionospheric delay rather than using CODE GIM. The peak-to-peak value of the ionospheric delay for TWCP in Bernese is about 10 ps, and this has to be eliminated to get high precision TWCP results. The $10^{-16}$ level uncertainty of atomic clock corresponds to 10 ps for 1 day averaging time, so time synchronization performance needs less than 10 ps. Current time synchronization of a satellite and ground station is about 2 ns level, but the smaller required performance, like less than 1 ns, the better. In this perspective, since the ionospheric delay could exceed over 100 ps in a long baseline different from this short baseline case, the elimination of the ionospheric delay is thought to be important for more high precision time synchronization of a satellite and ground station. This paper showed detailed method how to eliminate ionospheric delay for TWCP, and a specific case is applied by using this technique. Anyone could apply this method to establish high precision TWCP capability, and it is possible to use other software such as GIPSYOASIS and GPSTk. This TWCP could be applied in the high precision atomic clocks and used in the ground stations of the future domestic satellite navigation system.

• 대한음성학회지:말소리
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• 제2호
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• pp.2-8
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• 1981

• 한국콘텐츠학회논문지
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• 제8권11호
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• pp.356-363
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• 2008

축제의 양적 팽창에도 불구하고 지역축제에 대한 만족도는 몇몇 축제를 제외하곤 그리 높은 편이 아니다. 이는 지역축제의 본질적 목적에 비해 경제성을 강조한 나머지 지역축제의 개최목적인 지역관광산업의 발전, 지역문화의 보전, 지역주민의 여가기회확대, 지역공동체 의식의 함양, 지역이미지 제고 등을 고려하지 못한 축제들이 우후죽순 생겨나고 지역주민과 관광객의 만족을 높일 수 있는 행사내용과 형식들이 차별화되어 있지 못한 것에 기인한다고 볼 수 있다. 본 연구에서는 이러한 점을 고려하여 문화체육관광부의 축제평가기준을 토대로 제24회 김포문화예술제에 참여한 관광객과 지역주민에 대한 설문조사를 실시하여 지역축제 만족도 결정요인을 규명하고 이를 통해 지역주민과 관광객간의 재방문의도와 추천의도에 미치는 영향을 분석하여 향후 김포문화예술제가 성공적인 지역축제가 될 수 있도록 축제마케팅 전략수립에 유용한 시사점을 제공한다.

• 수산해양기술연구
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• 제46권4호
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• pp.406-415
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• 2010

The forming of fishing ground and the population ecological characteristics of yellowtail, Seriola quinqueradiata, in the coastal waters off Gim-nyeong of Jeju Island were investigated. The stock of yellowtail, Seriola quinqueradiata, between Jeju Island and coastal areas of the East Sea is probably the same. Water temperature probably is a major factor for controlling distribution of yellowtails in deeper, offshore areas off Jeju Island. However, the major factor that determines aggregation of yellowtails in coastal areas of Jeju Island, especially off Gim-nyeong is probably strong tidal currents driven by distribution of yellowtails rather than hydrological conditions such as Yellowtails collected off Jeju Island were from 1 to 4yrs old and about 50% of them were $1^{-yr}$ old, probably indicating overfishing. Jack mackerel was the major prey item for yellowtails off Gim-nyeong from October to March, suggesting concurrence of the two species.

• 한국측량학회지
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• 제28권4호
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• pp.413-420
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• 2010

현재 전리층 지연은 GNSS 측량의 가장 큰 오차이다. 단일 주파수 수신기 사용자는 전리층 지연을 모델링 하거나 보정하기 위하여 전리층 보정 알고리즘을 적용해야 한다. 실시간 보정이 가능한 전리층 모델로는 항법메시지로 제공되는 GPS의 Klobuchar 모델과 Galileo의 NeQuick 모델이 있다. 이 연구에서는 두 모델의 효용성을 계절과 위도에 따라 평가하였다. 첫 번째 검증으로, 각 계절별로 수원 GPS 상시관측소 상공의 연직방향 총전자수를 산출하였다. 두 번째 검증으로는 위도가 서로 다른 3개 상시관측소(철원, 수원, 제주)에서의 VTEC을 계산해 관측소 위도와의 상관성을 분석하였다. 산출된 총전자수는 전지구 전리층 모델인 GIM 모델과 IRI 모델에서 제공하는 총전자수와 비교하였다. 그리고 GIM 모델과 IRI 모델을 기준으로 Klobuchar 모델과 NeQuick 모델의 RMS 차이를 각각 산출하였다. 그 결과, 계절과 관측소 위도와 무관하게 NeQuick 모델의 RMS 차이가 Klobuchar 모델의 RMS 차이보다 약 0.01~3.50 TECU 낮게 나타났다.

• 동양고전연구
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• 제37호
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• pp.161-188
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• 2009

조선에 투항한 왜인을 항왜라 한다. 특히 임란전후에 수많은 왜인들이 조선인이 되어 살았는데, 고전 서사에서 이들의 모습이 어떻게 드러나는지 이글에서 살폈다. 고전서사에서 항왜는 주로 칼솜씨가 좋은 용맹한 인물들로 소개되며, 그러므로 그들은 각종 전쟁의 상황에서 전공(戰功)을 세우는 것으로 드러난다. 홍세태의 "김영철전"과 권칙의 "강로전" 및 김충선에 대한 인물전 등에서 이런 모습이 드러난다. 이런 작품에서, 항왜인들은 조선의 은혜에 감사하면서 오랑캐인 후금(後金)(이후 청(淸))을 치는 데에 앞장서는 모습을 보인다. 항왜인들이 이런 충성의 모범으로 그려짐으로써, 충성을 다해야 하지만 실제로는 그렇지 못했던 인물들의 불충이 상대적으로 부각되도록 그려졌다. 하지만 서사에서 의도적으로 항왜인들의 일면만을 강조되는 것과 달리, "검승전"에서는 항왜 개인의 고민과 갈등을 엿볼 수 있다. 이런 고민은 조선인이나 일본인이나 인간의 성정은 공통된다는 점을 보여줌으로써 서로 이해하며 어우러져 살 수 있는 가능성을 보여주기도 한다.

• 한국농촌건축학회논문집
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• 제20권1호
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• pp.77-84
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• 2018

Pungsu theory is one of the main factor influenced on the traditional village and house in Korea. Regarding the fact that a real effect of pungsu on the formation of traditional village and house, Study with a view of Pungsu theory could be a good method for deeply understanding the traditional architecture in Korea. In this context, this study analyzes the Gim, Hang Mug's house which is designated no. 136 as an important folk cultural heritage, located in 20, Chilseong-ro $4^{th}$ street, Chilseong-myon, Goesan-gun Chungbuk province. The analysis of the site and space lay-out is carried out by Yong(Dragon), Hyoel(Auspicious Spot), Sa(Sands), Su(Water) aspects of the Pungsu(Fengshui) Hyungsei-ron. Through the study, I find that there are many efforts to preserve the auspicious energy and minimize the negative influence from the transformed process from the early lay out of house to upper class residence having many attached buildings by laying out buildings after carefully observing and analyzing surrounding geographical features according to Pungsu theory.

• Journal of Positioning, Navigation, and Timing
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• 제9권1호
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• pp.1-6
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• 2020

The Chinese BeiDou Satellite Navigation System consists of three kinds of constellations: the geostationary Earth orbit (GEO), the inclined geosynchronous satellite orbit (IGSO), and the medium Earth orbit (MEO). The BeiDou has expanded its service coverage from regional to global. Recently, the BeiDou has been widely used in ionospheric total electron content (TEC) research. In this study, we analyzed the BeiDou signals for ionospheric TEC monitoring over Jeju Island in South Korea. The BeiDou GEO TEC showed a clear pattern of diurnal variations. In addition, we compared the TEC values from the BeiDou GEO, the BeiDou IGSO, GPS, and International GNSS Service (IGS) Global Ionosphere Maps (GIM). There was a difference of about 5 TEC units between the BeiDou GEO and the IGS GIM. This may be due to the altitude difference between the different navigation satellites.