• Journal of the Korean earth science society
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• v.22 no.2
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• pp.138-146
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• 2001

The land cover over Korean peninsula was classified using a multi-temporal NOAA/AVHRR (Advanced Very High Resolution Radiometer) data. Four types of phenological data derived from the 10-day composited NDVI (Normalized Differences Vegetation Index), maximum and annual mean land surface temperature, and topographical data were used not only reducing the data volume but also increasing the accuracy of classification. Self organizing feature map (SOFM), a kind of neural network technique, was used for the clustering of satellite data. We used a decision tree for the classification of the clusters. When we compared the classification results with the time series of NDVI and some other available ground truth data, the urban, agricultural area, deciduous tree and evergreen tree were clearly classified.

• Journal of Ocean Engineering and Technology
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• v.23 no.5
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• pp.25-31
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• 2009

The most important component of wind turbine is rotor blades. The developing method of wind turbine was focused on design of rotor blade. By the way, the design of a rotating body is more decisive process in order to adjust the performance of wind turbine. For instance, the design allows the designer to specify the wind characteristics derived by topographical map. The iterative solver is then used to adjust one of the selected inputs so that the desired rotating performance which is directly related to power generating capacity and efficiency is achieved. Furthermore, in order to save the money for manufacturing the rotor blades and to decrease the maintenance fee of wind power generation plant, while decelerating the cut-in speed of rotor. Therefore, the design and manufacturing of rotating body is understood as a substantial technology of wind power generation plant development. The aiming of this study is building-up the profitable approach to designing of rotating body as a system for the wind power generation plant. The process was conducted in two steps. Firstly, general designing and it’s serial testing of rotating body for voltage measurement. Secondly, the serial test results above were examined with the CFD code. Then, the analysis is made on the basis of amount of electricity generated by rotor-blades and of cut-in speed of generator.

• The Journal of Engineering Geology
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• v.12 no.3
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• pp.305-317
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• 2002

Geological, structural, and fracture density maps were drawn up to clarify the groundwater flow system around the Geumjeong Mountain, Busan. The results show that the topographical basin formed in the Sanseong Town is considered as a major recharge area of groundwater around the Geumjeong Mt. Because NS-trending fault and ENE-trending fault are intersecting and NS-trending and EW-trending fracture sets are highly developed in the basin, it is believed that the geological structure was developed in the basin which facilitates ground recharge. Based on the density distributions and characteristics of fractures, it is possible that the recharged groundwater in the basin would circulate to the depth of about 3~4 km and finally would reach the Dongnae Hot-spring region.

• Water for future
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• v.15 no.2
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• pp.23-32
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• 1982

This study is to clarify the relation between the maximum 24 hour rainfall and the daily rainfall of a designated time 10 A.M., using the 506 rainfall datum from 32 rain-guage stations on the Han river basin covering a period of 7 years and trying to estimate the ratio of two data in accordance with the amount of rainfall respectively. The Mononobe's formula, which is widely used in this country, has the value of 2/3 power in it. The "n" was considered instead of 2/3 and derivated for each guaging station. The results make it possible to establish the Ison-n value map, and show that the n value is affected mainly by the topographical conditions. The daily rainfall of a designated time can be modified by the results of this study and expressed as Y(%)=218.25/R$$. But in the case of exceeding 200mm/day, it is recommended to use the 110% for safety. On the problems of intensity-duration concerned with the planning of public works, the formula can be expressed as r$$=fRday/24.(24/t)$$, where "f" is Y(%) divided by 100. As this study was done with the datum within shor period, it is necessary to study more about the "n" and "f" value so as to get previse value in the future.o as to get previse value in the future.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.15 no.2
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• pp.157-164
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• 1997

This study deals with GPS-photogrammetry practicability by C/A-code reception. It allows data to be acquired and analyzed fast. Combined block adjustment method was applied at the topographical map production of coast-land. And we compared it that of conventional block adjustment. As a result, it was found that accuracy was very sensitive to the arrangement and number of control points. The accuracy in the horizontal and vertical was $\pm{2cm}$ if all of the control points was available. however accuracy was not affected at additional parameters for systematic errors' elimination and it leads to bad results when the number of control points was few and arrangement of control points was not stabilized. GPS observations were added in block adjustment, but the accuracy of block was not upgraded due to the low accuracy of C/A-code reception. So relative positioning method with carrier phases was required for high accuracy and it is expected that CPS photogrammetry with C/A-code will be used widely according to the improvement of observation methods and the development of receiver.

• Magazine of the Korean Society of Agricultural Engineers
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• v.12 no.4
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• pp.2078-2083
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• 1970

The purpose of this study is to give the data neccesary for improving the planning of drainage structures, specially inverted siphons, in irrigation channels. With the samples of 15 drainage inlets, one drainage flume, 16 drainage inverted siphons and 6 drainage culverts in the 3 lines of irrigation channel under Chong-Won Irrigation Association, author abtained the following results. 1. It is presumed that design drainage discharge should be determined with some additional reserves, on the basis of the maximum rainfall intensity in local area and the size of drainage area on the topographical map, avoiding the way of eye measure. 2. Location of drainage inlet should be kept away from the place where topography can make lots of wash load, but when unavoidably allowing the inflow into irrigation channel, wash load outlet with even the purpose of drainage, or drainage flume in stead of drainage inlet should be taken account of. 3. It is presumed that drainage flume may be the structure which can perform its function from a structural point of view as far as topography permits. 4. Drainage inverted siphon should be avoided at any place as much as possible; a) In case that location of the siphon would be permitted only at paddy field, drainage area hauing the amount of discharge which requires more than 90cm in diameter could only be allowed. b) In this case, crest elevation of the tank of both inlet and outlet, at least, should not be lower than the surface level of paddy field. c) As far as topography and stratum permit, ratio of depth of outlet tank to head drop should be decreased as much as possible so that discharging efficiency of wash load could increase. d) In case of avoiding the setting of the siphon, irrigation aqueduct, irrigation inverted siphon, or drainage flume should be recommended in accordance with topography. 5. Discharging capability of wash load by drainage culvert appeared to depend hardly upon the diameter of the culvert, but greatly upon the location, specially near village, for there stones and dirts dumped may considerably be piled up. So, a counter plan for that is required.

• Journal of Korean Society for Geospatial Information Science
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• v.11 no.1 s.24
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• pp.3-12
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• 2003

The main objective of this study is to extract the hydro-Parameter of the Tamjin River basin. A CIS is capable of extracting various hydrological factors from DEM. One of important tasks for hydrological analysis is the division of watershed. In this study, watershed itself and other geometric factors of watershed are extracted from DEM by using a CIS technique. The data of topographical map with scale of 1:25,000 and 1:250,000 in the Tamjin River basin is used for this study and it is converted to DEM date. Various forms of representation of spatial data are handled in main modules and a CRID module of ArcView. A GRID module is used on a stream in order to define watershed boundary. Based on the spatial analysis using those GIS technique, it would be possible to obtain the reasonable results of watershed characteristics. Also, the results show not only that GIS can aid watershed management, research and surveillance, but also that the geometric characteristics as parameters of watershed can be quantified more accurately and easily than conventional graphic methods. From the equations($Y=14632.87{\cdot}X^{-0.542444},\;Y=37014.1{\cdot}X^{-1.058808}$), it can be concluded that the optimal count of flow accumulation is 468 and cell size is 42m for spatial analysis by using GIS technique in Tamjin River basin.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.10
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• pp.901-906
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• 2010

A three-dimensional flow simulation was performed to investigate the flow field in a wind farm on a complex terrain. The present study aims to examine the effects of mountainous terrain and turbine arrangement on the performance of wind power generation. A total of 49 wind turbines was modeled in the computational domain; detailed blade shape of the turbines was considered. Frozen rotor method was used to simulate the rotating operation. The torque acting on the turbine blades was calculated to evaluate the performance of the wind turbines. The numerical results showed details of the flow structure in the wind farm including the velocity deficit in the separated flow regions; this velocity deficit was due to the topographical effect. The effect of the wake induced by the upstream turbine on the performance of the downstream wind turbine could also be observed from the results. The methodology of the present study can be used for selecting future wind-farm sites and wind-turbine locations in a selected site to ensure maximum power generation.

• Journal of the Korean Solar Energy Society
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• v.31 no.6
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• pp.8-22
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• 2011

Investigations on modeling methods of a CFD wind resource prediction program, WindSim for a ccurate predictions of wind speeds were performed with the field measurements. Meteorological Masts having heights of 40m and 50m were installed at two different sites in complex terrain. The wind speeds and direction were monitored from sensors installed on the masts and recorded for one year. Modeling parameters of WindSim input variables for accurate predictions of wind speeds were investigated by performing cross predictions of wind speeds at the masts using the measured data. Four parameters that most affect the wind speed prediction in WindSim including the size of a topographical map, cell sizes in x and y direction, height distribution factors, and the roughness lengths were studied to find out more suitable input parameters for better wind speed predictions. The parameters were then applied to WindSim to predict the wind speed of another location in complex terrain in Korea for validation. The predicted annual wind speeds were compared with the averaged measured data for one year from meteorological masts installed for this study, and the errors were within 6.9%. The results of the proposed practical study are believed to be very useful to give guidelines to wind engineers for more accurate prediction results and time-saving in predicting wind speed of complex terrain that will be used to predict annual energy production of a virtual wind farm in complex terrain.

• Journal of architectural history
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• v.24 no.3
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• pp.31-41
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• 2015

This study aims to draw out planning principles and structure of Iksan imperial capital city in late Baekje, especially in view of the relationship among imperial capital city planning area, skeletal axis and the location of royal castle. With site survey and analysis of historical records, old maps, topographical maps, archeological excavation data, land registration map of 1915, some significant inferences were drawn out. Firstly from the point of topological conditions, the contiguous line of a stratum from Mireuk mountain(彌勒山) to Wangkung-ri castle(王宮里遺蹟) and two waterways made a topological axis of Iksan Imperial capital city. Secondly district of Iksan imperial capital city can be deduced to the inner area north to Kummado soil wall(金馬都土城), south to the confluence of Iksan river(益山川) and Busang river(扶桑川), west to Okum mountain fortress(五金山城) and Galjeon river(葛田川), east to line near to eastern wall of Jesuksa temple(帝釋寺). Iksan ssang-reung(益山雙陵) was located outside western boundary line of capital city. Thirdly axis from Wangkung-ri castle to northern Kummado soil wall made a skeletal axis of city structure. It got through northern lowland along Buk river(北川) between Yonghwa(龍華山) and Mireuk mountain. Fourthly the location of royal palace can be deduced to the north part of the city around Kumma town area along the planning principle of northern royal palace.