• Geotechnical Engineering
• /
• v.13 no.3
• /
• pp.63-76
• /
• 1997

To investigate the engineering characteristics of crushed rockfill material, the large-scaled triaxial tests have been carried out, The rpckfill is made from the greywacke, and the 3 parallel gradations with different maximum particle size(dmu=38.1mm, 25.4mm and 19.1mm) were designed for the test. The dimension of the specimen is 300mm in diameter and 600mm in height, and the applied confining stress varied from 5t/$51.6^{\circ}$ to 60t/$51.6^{\circ}$. The test results show that the influence of the maximum particle size on the stress -strain r$51.6^{\circ}\; to\; 40.5^{\circ}$ when the confining stress increases from 5t/$51.6^{\circ}$ to 60t/$51.6^{\circ}$ The hyperbolic parameter values estimated from the test result for rockfill are much different from the recommended values by Duncan et. at(1980) for GW and GP material, especially in the $\phi$ ad K-values.

• Journal of Korean Society for Geospatial Information Science
• /
• v.13 no.1 s.31
• /
• pp.63-69
• /
• 2005

Interferometric Synthetic Aperture Radar(InSAR) is a rapidly evolving technique. Spectacular results obtained in various fields such as the monitoring of earthquakes, volcanoes, land subsidence and glacier dynamics, as well as in the construction of Digital Elevation Models(DEMs) of the Earth's surface and the classification of different land types have demonstrated its strength. As InSAR is a remote sensing technique, it has various sources of errors due to the satellite positions and attitude, atmosphere, and others. Therefore, it is important to validate its accuracy, especially for the DEM derived from Satellite SAR images. In this study, Real Time Kinematic(RTK) GPS and Kinematic GPS positioning were chosen as tools for the validation of InSAR derived DEM. The results showed that Kinematic GPS positioning had greater coverage of test area in terms of the number of measurements than RTK GPS. But tracking the satellites near and/or under trees md transmitting data between reference and rover receivers are still pending tasks in GPS techniques.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.16 no.4
• /
• pp.54-63
• /
• 2013

In this paper, we evaluate the accuracy of the vertical positioning by distance using Network RTK-GPS. The experimental results confirm that Network RTK-GPS method can acquire data quickly and accurately than conventional leveling methods so that the Network RTK-GPS method is a relatively efficient and economical way for the vertical positioning. Results of validation using permanent GPS stations indicate that visible satellites, PDOP, and VDOP are very good for the vertical positioning. Integrated reference points such as U0997 and U0921 are satisfied with 3 ratings in the rules of public leveling and all the rest are proved improper. When the vertical positioning using Network RTK-GPS is implemented, the geoid height of EGM2008 should be applied for leveling. If the number of geodetic satellite are increasing in the near future, the vertical positioning using Network RTK-GPS can be possible in all the range.

• Proceedings of the KIEE Conference
• /
• 2008.04a
• /
• pp.63-64
• /
• 2008

GPS의 활용 분야는 군용 항법 시스템에서 항공, 선박 등의 개인 항법 시스템으로 확장되었다. GPS가 넓은 범위에서 응용됨에 따라 Jamming과 같은 고의적인 간섭 신호의 제거에 대하여 많은 연구가 진행되었다. 그러나 기만 신호의 특성이나 기만 기법에 대한 연구는 미비하다. 본 논문에서는 기만 신호의 구조와 기만 개념을 연구하였으며 기만신호의 생성 기법으로 항법 메시지를 이용한 기법과 GPS PRN 코드를 이용하여 TOA(Time of Arrival)에 오차를 인가하는 기법을 정리하고 이중 TOA에 오차를 인가하는 방식을 GPS 소프트웨어 플랫폼에 구현하여 기만신호를 생성하였다. 또한 기만 신호 대응 기법의 개발 텐 성능 분석을 위하여 소프트웨어 GPS 수신기를 이용하여 생성한 기만 신호가 GPS 수신기에 미치는 영향을 분석하였다.

• Journal of Korean Society for Geospatial Information Science
• /
• v.6 no.1 s.11
• /
• pp.53-63
• /
• 1998

The purpose of this study is to investigate the current status of automatic measuring systems for air pollution emissions in Seoul and to suggest an improvement method using GIS and GPS. In Korea, there have been very few critical researches and managements for mobile and area sources regarding moving subjects such as automobiles. In order to control or to make a plan for reducing air pollutions, air pollution emission data based on tim and location, emission inventory systems and emission models should be implemented. Using digital maps and MS Visual Basic, we developed a visualized interface for air pollution emission data from automatic emission measurement systems in Seoul.

• Korean Journal of Agricultural Science
• /
• v.38 no.4
• /
• pp.641-649
• /
• 2011

This study was to analyze the soil environmental characteristics and vegetation status of green roof in Daejeon Metropolitan City. The investigated floras of vascular plants are 17 families, 26 genera, 28 species in Seo-Gu Daejeon District Office Building (SG), 25 families, 49 genera, 56 species in Galma Public Library (GP), and 34 families, 57 genera, 60 species in Daejeon City Hall (DC) respectively. Although the larger area shows the more numbers of species in introduced plants and naturalized plant, the naturalized plant ratios were similar with each other. They were 10.71%, 10.71%, and 11.67% at SG, GP, and DC respectively. As a result of analysis on soil physical property, soil depths including vegetation soil and drainage soil of 3 green roofs were 30cm. The depths of vegetation soil at SG, GP, and DC were 0~8cm, 0~10cm, 0~10cm respectively. As a results of soil chemical properties of our study, soil pH of vegetation soil and drainage soil were a range of 6.42 and 7.43, and a range of 6.55 and 7.43 on the average respectively. Available-P contents of vegetation soil and drainage soil were a range of 153.33 and 366.33mg/kg, and a range of 136.67 and 242.67 mg/kg which is very high, respectively. Carbon contents in soil at vegetation soil and drainage soil were a range of 3.16 and 6.38%, and a range of 1.63 and 2.47% respectively. Carbon storage per square meter within 30 cm were 2.76 kg, 2.99 kg, and 3.66 kg at SG, GP, and DC respectively.

• Food Science and Preservation
• /
• v.25 no.1
• /
• pp.44-51
• /
• 2018

The purpose of this study is to present the results as basic data for establishing proper storage conditions and distribution conditions of actual farms at point of increasing concern about hygiene and palatabiltiy of consumers to food. In this study, three farmhouses of dried persimmons prepared using different storage conditions were selected in Sangju (Korea). The dried persimmons were stored for 90 days. Changes in temperature and humidity were measured with a temperature and humidity recorder under each storage condition, and physicochemical analysis and sensory evaluation were performed. The average temperatures of farmhouse A, B and C were approximately $-22--23^{\circ}C$, $-19--18^{\circ}C$ and $-25^{\circ}C$ respectively. The humidities of A, B and C were 62-63%, 59-60%, and 66-67%, respectively, and the moisture contents of all farmhouses increased during the storage period, with farmhouse B showing the most rapid increase. Free sugars increased, except for those from farmhouse C. Persimmons from farmhouse B showed the greatest changes in chewiness and hardness. The values of $a^*$ and $b^*$ were significantly decreased in persimmons from farmhouse B, and the color difference value of farmhouse B was dramatically increased. Sensory evaluation showed that the color preference tended to decrease compared with the initial value. Only farmhouse B showed decreased overall acceptability. Moreover, farmhouse B had the highest storage temperature and lowest humidity. Therefore, our results showed that storage at a low temperature and high humidity was important for manufacturing high-quality dried persimmons.

• Journal of the Korean Society of Physical Medicine
• /
• v.10 no.2
• /
• pp.63-71
• /
• 2015

PURPOSE: The purpose of this study to investigate the effects of exercise on lumbar stabilization in muscle activity and isokinetic muscle strength of female with chronic low back pain. METHODS: The candidates was chose to twenty women in their 30s and 40s complaining back pain for over 12 weeks and consist of 10 people for lumbar stabilization and general physical therapy group(PL group), another 10 people for general physical therapy group(GP group). Lumbar stabilization exercise was conducted for 8 weeks and was comprised of 60 minutes for two times a week. In order to examine the effects of lumbar stabilization, results in the present study were analyzed maximal voluntary isometric contraction (MVIC) using electromyogram to measure muscle activity and isokinetic performance including peak torque and average power at the pre to post. RESULTS: The following are results in this study. The MVIC and isokinetic muscle strength were gradually increased in all group. As the result of the test of the MVIC and isokinetic muscle strength, the difference of lumbar stabilization and general physical therapy group is statistically more significant than that of general physical therapy group. CONCLUSION: In the present study, results indicate that lumbar stabilization helps to improve the muscle activity and isokinetic muscle strength.

• Journal of Astronomy and Space Sciences
• /
• v.18 no.1
• /
• pp.63-70
• /
• 2001

IDGPS(Inverted Differential Global Positioning System) is one of technique improving the accuracy of GPS positioning and is mostly used for tracking an automatic vehicle. In the IDGPS, the user send it’s GPS position and related satellite information to dispatcher, and the corrections are made at the dispatcher to get corrected user position. IDGPS suffered correction degradation as the baseline become large. This problem is resolved using NIDGPS(Network IDGPS). As the experimental results are demonstrated, the improvement of position accuracy using IDGPS and NIDGPS is verified.

• ICROS
• /
• v.3 no.2
• /
• pp.58-63
• /
• 1997

GPS 응용 기술 중에서 항공우주에 연관된 2분야인 비행체 항법과 위성체 자세 결정 및 항법에 대해 알아보았다. 그밖의 중요한 GPS의 응용으로 자동차 항법 및 추적, 항공교통 통제, 측량, 측지학, 선박의 항법 및 추적, 시각동기 등이 있다. 항공기의 항법장치는 그 정확도와 안전도가 매우 엄격하기 때문에 가장 진보된 GPS 응용기술이 요구되고 있다. 따라서 항공기 항법장치의 개발은 다른 GPS 응용에 대한 파급 효과가 크기 때문에 무척 중요하다고 하겠다. 서기 2000년대에 광역위성항법시스템(WAAS)이 본격적으로 작동하게 되면 미국은 항공에 관한 사업만으로도 약 20억불을 절약할 수 있게 된다. 한국에서도 4-5개의 광역기준으로 구성되는 광영위성항법시스템을 구축하면 착륙접근을 위한 공간이 충분하지 않은 많은 공항들에 대해 항공기 착륙유도에 대한 안전도와 신뢰도를 높일 수 있고 따라서 항공기 사고를 효과적으로 예방할 수 있게 된다. 광역위성항법 시스템은 항공기 뿐만 아니라, 자동차나 선박 그리고 다른 GPS 응용에 있어서도 그 정확도와 안전도를 높이는데 이용될 수 있다.