• Economic and Environmental Geology
• /
• v.39 no.4 s.179
• /
• pp.441-450
• /
• 2006

The on-land seismic survey in Korea was begun in mid-1960s. Kim et al.(1967) of Korea Geological Survey reported on the result of gravity and seismic reflection surveys conducted in the Pohang area for the period of 1963-64 to assess its possibility of oil entrapment. Hyun and Kim (1966) carried out a refraction survey on the tunnel wall. Since then, the KGS geophysicists had conducted seismic surveys on Kyungsang sedimentary basin as a main project for several years. In 1970s, on-land seismic surveys had been conducted for various purposes such as site investigation for the nuclear power plants and industrial complex, exploration for ground water, mineral resources and underground tunnel. The first reflection survey with CMP acquisition was attempted in 1978 by using a digital recording system. But most of on-land seismic surveys had employed the refraction method until 1980s. In 1990s, high resolution reflection and various borehole seismic surveys such as tomography, uphole, downhole, cross-hole methods have been attempted by universities and engineering companies. The applications of on-land seismic surveys have been enlarged for both academic and industrial purposes such as investigation of geologic structure of the fault and tidal flat area, construction of highway, railroad and dam, geothermal energy and mineral resource exploration, environmental assessment for waste disposal sites and archaeological investigations. In 2002, the first crustal seismic survey was carried out on the profile of 294km length across the whole peninsular. It is expected that the advanced technology and experience acquired through offshore seismic surveys, which have been conducted in continental shelf of Korea and foreign oil fields, will stimulate the more active on-land seismic explorations.

• Journal of Radiation Protection and Research
• /
• v.45 no.2
• /
• pp.76-80
• /
• 2020

Background: To improve the measurement accuracy of liquid-scintillation counting for activity standardization, it is necessary to significantly reduce the background caused by thermal noise or after-pulses. We have therefore improved a movable 3 photomultiplier (3PM)-γ coincidence-counting method using the logical sum of three double coincidences for β events. Materials and Methods: We designed a new data-acquisition system in which β events are obtained by counting the logical sum of three double coincidences. The change in β-detection efficiency can be derived by moving three photomultiplier tubes sequentially from the liquid-scintillation vial. The validity of the method was investigated by activity measurement of ¹³⁴Cs calibrated at the Korea Research Institute of Standards and Science (KRISS) with 4π(PC)β-γ(NaI(Tl)) coincidence counting using a proportional counter (PC) for the β detector. Results and Discussion: Measurements were taken over 14 counting intervals for each liquidscintillation sample by displacing three photomultiplier tubes up to 45 mm from the sample. The dead time in each β- and γ-counting channel was adjusted to be a non-extending type of 20 ㎲. The background ranged about 1.2-3.3 s^-1, such that the contributions of thermal noise or after-pulses were negligible. As the β-detection unit was moved away from the sample, the β-detection efficiencies varied between 0.54 and 0.81. The result obtained by the method at the reference date was 396.3 ± 1.7 kBq/g. This is consistent with the KRISS-certified value of 396.0 ± 2.0 kBq/g within the uncertainty range. Conclusion: The movable 3PM-γ method developed in the present work not only succeeded in reducing background counts to negligible levels but enabled β-detection efficiency to be varied by a geometrical method to apply the efficiency extrapolation method. Compared with our earlier work shown in the study of Hwang et al. [2], the measurement accuracy has much improved. Consequently, the method developed in this study is an improved method suitable for activity standardization of β-γ emitters.

• The Korean Nurse
• /
• v.33 no.3
• /
• pp.56-69
• /
• 1994

This study was done to develop self - directed learning modules related to asepsis and elimination including urine and stool for Fundamentals in Nursing practice education contents and to measure the effectiveness of those modules. The subjects of this study were 96 sophomore students in the nursing college. Self-directed learning modules were developed by the researcher on the basis of the Lippincott Learning System of Kruger (1986) and Modules for Basic Nursing Care of Ellis (1992). Videotape was editted by using videotape made by the Lippincott Company and Film strip made by the Trainex Company with Korean dubbing. Self-directed learning was done for one week with the asepsis module and two weeks with the elimination modules after confirming the requiered level of knowledge acquisition through pre-test. For measuring proficiency in self-directed learning, a written test for cognitive domain, a sufficiency test for psychomotor domain, and a confidnece examination for affective domain were given. The data were analyzed using descritive statistics, and Pearson correlation coefficient using a SPSS-PC program. The results are summarized as follows: 1. Sufficiency test and confidence examination grades showed high levels in both asepsis and elimination. 2. Written test grades showed a high level in asepsis and elimination of urine but showed a medium level in eliminationin of stool. 3. Grades of sufficiency and confidence in asepsis and elimination practice were statistically significant with a moderate positive correlation (r=0.4- 0.5, p<0.001). 4. Grades of sufficiency and written tests in asepsis and elimination practice also were statistically significant with a moderate positive correlation (r=0.5-0.7, p<0.001). 5. Students showed relatively high contentment with the self-directed learning modules themselves but revealed relatively low contentment with video program and the self-directed learning process. In conclusion, this study disclosed that proficiency levels in cognitive, affective, and psychomotor domains were high when asepsis and elimination modules were applied. Also students showed high satisfaction with the modules themselves, but didn't show high contentment with the video programs. In considering low contentment with the self-directed learning process, it is estimated the students had experienced some difficulties about using self-directed learning modules because this was their first exposure to the self-directed learning module and they were already accustomed to the demonstration-practice method.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.40 no.3
• /
• pp.181-189
• /
• 2016

An analytical model was developed by Sim to estimate the two-phase damping ratio for upward two-phase flow perpendicular to horizontal tube bundles. The parameters of two-phase flow, such as void fraction and pressure loss evaluated in the model, were calculated based on existing experimental formulations. However, it is necessary to implement a few improvements in the formulations for the case of tube bundles. For the purpose of the improved formulation, we need more information about the two-phase parameters, which can be found through experimental test. An experiment is performed with a typical normal square array of cylinders subjected to the two-phase flow of air-water in the tube bundles, to calculate the two-phase Euler number and the two-phase friction multiplier. The pitch-to-diameter ratio is 1.35 and the diameter of cylinder is 18mm. Pressure loss along the flow direction in the tube bundles is measured with a pressure transducer and data acquisition system to calculate the two-phase Euler number and the two-phase friction multiplier. The void fraction model by Feenstra et al. is used to estimate the void fraction of the two-phase flow in tube bundles. The experimental results of the two phase friction multiplier and two-phase Euler number for homogeneous and non-homogeneous two-phase flows are compared and evaluated against the analytical results given by Sim's model.

• Land and Housing Review
• /
• v.5 no.3
• /
• pp.137-149
• /
• 2014

The authors derived rental housing policy measures that are appropriate for the current conditions of Korean housing supply and demand based on the confirmation of the issues of Korean rental housing system and reviewing implications from review of cases of foreign countries and these measures can be categorized into linkage with the urban regeneration and multi-functional development, acquisition of financial resources, operational management, policy and institutional aspects. For the expansion of supply of rental housing, it is essential to link the rental housing policy with urban regeneration. To pursue regeneration of underdeveloped areas and expansion of supply of rental housing in line with urban regeneration, more development sites should be added. Further, the rental home policy must be integrated into a new paradigm that includes securing commercial viability and providing various residential conveniences through multi-functional development. In addition, diversification of developers of real estates turning away from the existing framework of policy that has been focused only on the state-led housing supply so that local governments and private sector players can take part in. Next, new options for funding the supply of rental housing must be sought. First, raising financial resources sequentially through cyclical development approach could be considered. Or, various funding schemes including utilizing Tax-increment financing (TIF) based on the local tax revenues that will be accrued after the development projects and supply of rental housing. Or there should be various schemes to raise funds including utilization of TIFs that are based on the revenues that will be realized after the development projects and supply of rental housing, or utilizing REITs where funds can be provided through private sector investments. Also, getting out from the planning practice that focused only on physical expansion of supply of rental housing, continual operational management must be performed even after the development. These activities must be supported through establishment of control tower at the national level and continuous attention must be paid even after the development by developing specialized operational management companies that are led by private sector players. Finally, in addition to the hardware support that is focused on the public rental housing only, software support such as conditional provision of housing voucher or tax exemption for low-income classes should be provided, too. In other words, a shift from policies that are supplier-centric to ones that are customer-centric must take place.

• Land and Housing Review
• /
• v.9 no.2
• /
• pp.9-19
• /
• 2018

The purpose of the study is to show the possibility of the enlargement of land banking types through employment of the French land bank case. For sustainable urban regeneration projects, it is necessary to improve the land banking system with comprehensive land banking types. There are a total of 35 land banking agencies in France, which are made according to the needs of the municipality. The main function of these institutions is to perform functions such as land acquisition, management, division, land maintenance(decontamination, etc.), land use plan review and so on. In the 1960s and 1970s, mainly purchase and maintenance of land mainly focused on Brownfield and idle land, but since 2000 the land purchase business is mainly for the supply of social rental housing which is missing It was. The use of land banks is most frequently mentioned as a way of how to supply land at a low price in urban renewal projects. To that end, it is necessary to revise related laws, even if the law is revised so that land for urban regeneration projects can be secured, due to the limit of financial resources, land for the urban regeneration project nationwide secured It will not be easy without policy judgment of a positive nation. Therefore, securing land reserve resources for urban regeneration projects utilizing residential district funds and municipal maintenance funds is essential. In addition, even on a small scale, it is necessary to consider the banking of land for regional capitalization at the local government level.

• Journal of Cadastre & Land InformatiX
• /
• v.47 no.2
• /
• pp.79-90
• /
• 2017

Urban environment represent one of the most dynamic regions on earth. As in other countries, forests, green areas, agricultural lands are rapidly changing into residential or industrial areas in South Korea. Monitoring such rapid changes in land use requires rapid data acquisition, and satellite imagery can be an effective method to this demand. In general, SAR(Synthetic Aperture Radar) satellites acquire images with an active system, so the brightness of the image is determined by the surface roughness. Therefore, the water areas appears dark due to low reflection intensity, In the residential area where the artificial structures are distributed, the brightness value is higher than other areas due to the strong reflection intensity. If we use these characteristics of SAR images, settlement areas can be extracted efficiently. In this study, extraction of settlement areas was performed using TerraSAR-X of German high-resolution X-band SAR satellite and KOMPSAT-5 of South Korea, and object-oriented image classification method using the image segmentation technique is applied for extraction. In addition, to improve the accuracy of image segmentation, the speckle divergence was first calculated to adjust the reflection intensity of settlement areas. In order to evaluate the accuracy of the two satellite images, settlement areas are classified by applying a pixel-based K-means image classification method. As a result, in the case of TerraSAR-X, the accuracy of the object-oriented image classification technique was 88.5%, that of the pixel-based image classification was 75.9%, and that of KOMPSAT-5 was 87.3% and 74.4%, respectively.

• Journal of Korean Society for Geospatial Information Science
• /
• v.18 no.1
• /
• pp.89-97
• /
• 2010

The ship-borne gravity data is essential to construct geoid in Korea surrounding ocean area. The altimeter data was used in previous study, however, the ship-borne gravity data could be used due to more ship-borne data was collected by improvement of instrument, positioning system. Therefore, the study on verification of precision of ship-borne gravity data and practical usage analysis is needed. In this study, free-air anomaly having 16.47mGal and 18.86mGal as mean and standard deviation was obtained after consistent processing such as Eotvos correction, Kalman Filter, Cross-over adjustment etc. The calculated free-air anomaly was compared to DNSC08 altimeter data and the difference was computed having -0.88mGal and 9.46mGal of mean and standard deviation. The reason causing those differences are owing to spatial limits of data acquisition and effects of ocean topography. To use ship-borne gravity data for precision geoid development, the efforts to overcome the limits of data collection and study for data combination should be proceeded.

• Journal of Biosystems Engineering
• /
• v.41 no.3
• /
• pp.273-280
• /
• 2016

Purpose: This experiment was conducted to detect water stress in terms of the moisture content of cucumber seedlings under water stress condition using a hyperspectral image acquisition system, linear regression analysis, and partial least square regression (PLSR) to achieve a non-destructive measurement procedure. Methods: Changes in the reflectance spectrum of cucumber seedlings under water stress were measured using hyperspectral imaging techniques. A model for estimating moisture content of cucumber seedlings was constructed through a linear regression analysis that used the moisture content of cucumber seedlings and a normalized difference vegetation index (NDVI). A model using PLSR that used the moisture content of cucumber seedlings and reflectance spectrum was also created. Results: In the early stages of water stress, cucumber seedlings recovered completely when sub-irrigation was applied. However, the seedlings suffering from initial wilting did not recover when more than 42 h passed without irrigation. The reflectance spectrum of seedlings under water stress decreased gradually, but increased when irrigation was provided, except for the seedlings that had permanently wilted. From the results of the linear regression analysis using the NDVI, the model excluding wilted seedlings with less than 20% (n=97) moisture content showed a precision ($R^2$ and $R^2_{\alpha}$) of 0.573 and 0.568, respectively, and accuracy (RE) of 4.138% and 4.138%, which was higher than that for models including all seedlings (n=100). For PLS regression analysis using the reflectance spectrum, both models were found to have strong precision ($R^2$) with a rating of 0.822, but accuracy (RMSE and RE) was higher in the model excluding wilted seedlings as 5.544% and 13.65% respectively. Conclusions: The estimation model of the moisture content of cucumber seedlings showed better results in the PLSR analysis using reflectance spectrum than the linear regression analysis using NDVI.

• Journal of Astronomy and Space Sciences
• /
• v.20 no.1
• /
• pp.29-42
• /
• 2003

The KSR-3 magnetometers consist of the fluxgate magnetometer (MAG/AIM) for acquiring the rocket flight attitude information, and the search-coil magnetometer (MAG/SIM) for the observation of the Earth's magnetic fluctuations. The position (latitude, longitude, and height) and flight condition (the transformation angle) of the rocket is measured after the data based on these two magnetometers are compared with IGRF The gap in the vector of magnetic field between the position of the launching point and an impact point is taken into account in data reduction. Angular variation of pitch, yaw, and roll can be researched when the data is applied to the coordinate system of the rocket.