• Korean Journal of Optics and Photonics
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• v.32 no.1
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• pp.22-28
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• 2021

We try to extract three-dimensional information, such as the distance from a camera and the actual width and height of an object, from still photographs by a multilens smartphone camera, by means of parallax error. To obtain this information, we develop several formulas and design a method for experimental instrumentation. If the results from this paper were included in algorithms of multilens smartphone cameras, there would be various kinds of applications, such as in the workplace of architectural and civil engineering to obtain an actual dimension, or on a golf course to measure how far away a pin flag is. We expect many more applications of this study, because the multilens smartphone camera is already an important necessity of life.

• Journal of Korean Society of Rural Planning
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• v.27 no.4
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• pp.109-122
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• 2021

The purpose of this study is to develop a application procedure and survey method for the empirical diagnostic indices system. In order to know the survey method, which has 65 investigation items for 52 indicators, this study not only presented so that the each survey items could be surveyed in at least 1 to 3 steps, but also presented the 4 survey method for each investigation items: preliminary survey, administrative survey, field survey, and interview survey. As a result of applying to 15 sample villages, the period of surveying a village of 100 households was 1.4 days, and it was confirmed that the survey was generally efficient in a short time. As a result of applying the survey system to the sample village, the developed survey system showed the possibility of investigating even the details of rural villages. Therefore, it was judged that it could be used as a basic procedure for a rural village unit survey.

• Educational Technology International
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• v.15 no.2
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• pp.89-115
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• 2014

This research aims to develop an elementary school English e-learning system based on the 'Self-determination theory (SDT)', which is widely applied to traditional face-to-face foreign language classes. The study also attempts to verify whether SDT-a traditional motivational theory that has been applied to face-to-face classes- is effective in an e-Learning environment with students who use this newly developed system. For the purposes of this project, the following three actions were carried out. First, a motivational strategy based on SDT was deduced. In SDT, the needs for autonomy, competence, and relatedness were introduced as basic psychological needs, and assumed that these three needs provided the natural motivation for learning, growth, and development. Second, an e-Learning system was created based on the deduced motivational strategy. Third, the system was implemented in 115 private tuition academies, and education was provided to 1,400 users for one year across the country. Afterwards, by surveying users, correlation between the role of the three psychological needs in learning English, and also the correlation between each need and motivation were investigated. Research results showed that traditional motivational theories used in face-to-face classes so far were effective in an e-Learning environment.

• Journal of dental hygiene science
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• v.12 no.2
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• pp.79-84
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• 2012

The purpose of this study was to utilize it as useful basic data for improving oral health and for developing educational guidelines, by surveying the intake frequency in cariogenic food and the dietary intake status in detergent food through dietary life diary of some female undergraduates, and by researching into relationship between dietary intake factor and dental caries. It allowed dietary life diary for 5 days to be recorded targeting female undergraduates for the Dept. of Dental Hygiene, selected dietary life diary of 66 people without omission of record, and used it in this study. The following conclusions were obtained. 1. As a result of surveying the food intake status, it was indicated to be 12.82 for cariogenic food intake frequency, 256.36 for caries incidence available time and 8.32 for detergent food intake frequency. 2. As a result of surveying in order to examine relationship between cariogenic food intake frequency, detergent food intake frequency & cariogenic light-meal intake frequency and dental caries by dividing group with caries and group with non-caries, the group with caries was indicated to be a little higher than the group with non-caries. However, statistically significant difference wasn't indicated. 3. In the correlation between dietary intake status and dental caries, it was indicated that the more rise in cariogenic food intake frequency leads to the more rise in detergent food intake frequency and even in total light-meal intake frequency, but wasn't shown correlation with dental caries. In light of the above results, many limitations were indicated in finding and analyzing the dental caries incidence level and cause just with a method through surveying dietary intake. However, given the more in cariogenic food intake frequency and detergent food intake frequency, the possibility of dental caries incidence could be predicted.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.25 no.2
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• pp.117-131
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• 2007

Representation of building internal space is an active research area as the need for more geometrically accurate and visually realistic increases. 3 dimensional representation is common ground of research for disciplines such as computer graphics, architectural design and engineering and Geographic Information System (GIS). In many cases CAD plans are the starting point of reconstruction of 3D building models. The main objectives of building reconstruction in GIS applications are visualization and spatial analysis. Hence, CAD plans need to be preprocessed and edited to adapt to the data models of GIS SW and then georeferenced to enable spatial analysis. This study automated the preprocessing of CAD data using AutoCAD VBA (Visual Basic Application), and the processed data was topologically restructured for further analysis in GIS environment. Accuracy of georeferencing CAD data was also examined by comparing the results of coordinate transformation by using digital maps and GPS measurements as the sources of ground control points. The reconstructed buildings were then applied to visualization and network modeling.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.37 no.6
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• pp.453-464
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• 2019

Recently, as the demand for 3D geospatial information increases, the importance of rapid and accurate data construction has increased. Although many studies have been conducted to register UAV (Unmanned Aerial Vehicle) imagery based on LiDAR (Light Detection and Ranging) data, which is capable of precise 3D data construction, studies using LiDAR data embedded in MMS (Mobile Mapping System) are insufficient. Therefore, this study compared and analyzed 9 matching algorithms based on feature points for registering reflectance image converted from LiDAR point cloud intensity data acquired from MMS with image data from UAV. Our results indicated that when the SIFT (Scale Invariant Feature Transform) algorithm was applied, it was able to stable secure a high matching accuracy, and it was confirmed that sufficient conjugate points were extracted even in various road environments. For the registration accuracy analysis, the SIFT algorithm was able to secure the accuracy at about 10 pixels except the case when the overlapping area is low and the same pattern is repeated. This is a reasonable result considering that the distortion of the UAV altitude is included at the time of UAV image capturing. Therefore, the results of this study are expected to be used as a basic research for 3D registration of LiDAR point cloud intensity data and UAV imagery.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.2
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• pp.445-449
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• 2017

Most studies using drone is confined utilization on the ground and regulation. The drone in the water is rarely used in hydrographic surveying because of the limit of flight time and image matching. This paper is the basic research for drone hydrographic photogrammetry. The accuracy of hydrographic photogrammetry, using buoys for water reference point, was evaluated. The accuracy is influenced by the accuracy of the water reference points like the photogrammetry. The position of water reference points set up on water, keep on changing due to various environmental factors such as wind speed and water velocity. The position continuously changed of the water reference points were measured 3 times using Total Station and VRS. Experiments were conducted at two reservoirs in Gimhae City, and the accuracy of the manual image matching using the water reference points is 40 cm and 80 cm. Allowable accuracy of the ocean boundary survey is ${\pm}2m$, the results of this study are fully available. The maximum position error of the water reference point for ensuring accuracy within ${\pm}2m$ is 1.8 m.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.23 no.4
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• pp.345-352
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• 2005

In up-to-date information anger time it is caused by with business of traffic accident control and analysis and two time it accomplishes a business. National Police Office which controls a traffic accident does not execute an up-to-date technique. And, it is working yet by the hand, There is to traffic accident analysis and the research regarding the analysis against the research which it follows in geography element and composition element and an accident cause is weak. Consequently, effectively establishment and it enforces a traffic safety policy and from the hazard which it evaluates traffic accident data the system and scientific analysis against a traffic accident occurrence cause and a feature in basic must become accomplished. The research which it sees constructs a traffic accident data in GIS base. It is like that, it uses the PDA where is not the collection of data of text form in existing and at real-time it converts store and an accident data rightly in standard traffic accident data form and it will be able to manage. It was related with a space data peculiarity and the research regarding the system development with the geography analysis data about an accident cause under manifesting it accomplished.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.31 no.3
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• pp.239-247
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• 2013

The global gravitational model is essential for precision geoid model construction. Also, it would be used as basic scientific data in geophysical and oceanographic fields. In Korea, EGM2008 has been used from the late 2000s. After publishing EGM2008, new gravitational models such as GOCO02S, GOCO03S, EIGEN-6C, EIGEN-6C2 based on GOCE data were developed. Therefore, we need to verify recent models to select optimal one for geoid computation in Korea. In this study, we compared new models generated based on the GOCE data to EGM2008 and verified the precision of models by comparing with NGII(National Geographic Information Institute) GPS/Leveling data. When comparing EIGEN models to EGM2008, the difference is about 8cm. On the other h and, about 70cm of difference between GOCO models and EGM2008 has been calculated. The reason for this is because GOCO models have been developed using only satellite data while EGM2008 has been used gravity and altimeter data as well as satellite data. When comparing global gravitational model to GPS/Leveling data, EGM2008 showed the best precision of 6.1cm over whole Korean peninsula. The new global gravitational model using additional GOCE data will be published consistently, so the precision verification of new model should be continued.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.23 no.3
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• pp.293-301
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• 2005

In case of the roads that pass the mountain area, the cut sections or the tunnels are constructed. And In winter season it appears sunshine few in the specific segment, the shade is continued last and the freezing sections occur. So, the attention is necessary in traffic safety. This study was to evaluate the influence of sunshine and surface freezing sections expected in route plans of roads using GIS and makes alternative ideas in road stability security. After selecting 29 km sections of Donghae highway and creating a 3 dimensional terrain surface through the digital conversion of design plan data, it reflects the road alignment data of the same coordinates and a 3 dimensional road modeling is created. It set shadow time of road surface for the solar trace in the winter solstice in 20 minute interval. Shade areas are displayed and inputed in polygon data by manual vertorizing. Graphic and attribute data of this shade section is constructed in geodatabase of ArcCatalog. And it extracted the freezing section using intersect fuction of the GIS spatial analysis. By analyzing the winter meteorological data of temperature, rainfall, snowfall, humidity, and etc. and grasping dangerous freezing section of the road surface effectively, it will be able to make alternative ideas of the preliminary stability evaluation reflected in basic design.