• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.5 no.2
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• pp.24-33
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• 1987

This study aims at obtaining more effective image processing techniques and more accurately classified image in the sphere which uses remotely sensed data. For this practice, the result of land use classification compounding summer scene with winter scene and the classified result of summer scene were compared, analyzed. From the upper analysed results, we found that Bitemporal Classification technique and $tan^{-1}$transformation were effective. Particularly, dividing crop class into two classes of farmland and field was more possible by appling Bitemporal Classification technique.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.9 no.1
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• pp.63-73
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• 1991

The data type of the echo sounding for the contouring of coastal chart is continuous profiles, and there are no data between the profiles. In this study, at first, the depths of the regular grid along the sounding line were interpolated by linear equation. After that the depths of the regular grid located between the profiles were interpolated by kriging. The semivariogram contributes to the weight of interpolation. After comparison with the conventional Moving Average and Kriging, it turns out that this algorithm shows merits in the field of the accuracy and computing time.

• Geophysics and Geophysical Exploration
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• v.7 no.1
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• pp.1-6
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• 2004

High-resolution S-wave reflection surveying has been successfully conducted on paved areas using a Land Streamer originally designed by the author. The main feature of the Land Streamer tool is the non-stretch woven belt on which geophone units are mounted to form a multichannel geophone array similar to a marine streamer. Because it is easily towed by a vehicle or by hand, the tool leads to high performance in field measurements and resultant cost-effectiveness of high-resolution reflection surveys. Although each geophone unit is coupled to the pavement through a metallic baseplate instead of being firmly planted in the ground, the Land Streamer tool provides comparatively clean data, unaffected by traffic noise even on the pavement. Thus, the tool is capable of expanding the opportunity for S-wave reflection surveys in urban areas where many surfaces are paved and traffic noise is severe. A series of high-resolution S-wave reflection surveys on paved areas delineated detailed structures of surface layers shallower than 60 m, and proved the wide applicability of the tool to engineering, environmental applications, and earthquake disaster prevention projects.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.17 no.3
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• pp.197-203
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• 1999

Depending on geographical features and error sources in the survey field, inaccurate data is inevitable in GPS kinematic survey for positioning with feature codes. In this study, the trimmed mean and the first order differential equation are used to develop an inaccurate positioning data detection algorithm, and a cubic spline curve and a linear polynomial are used to interpolate the inaccurate data. Based on interpolated data, a digital map for 30 km range of rural highway is produced and a corresponding GIS coverage map is obtained by analyzing and solving the problem associated with the map.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.28 no.5
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• pp.515-522
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• 2010

With the development of information technology, the demand on digitalized space information is being largely expanded in our society. Especially, the recency securing of material as well as various policy alternatives like expansion on an application scope are being required in the spatial information utilization field, such as efficient use and management of the land, various spatial plans, environment and disaster management, etc. The present research aims to suggest an evaluation model by applying the system dynamics theory for dynamic analysis on utilization of this spatial information.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.21 no.3
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• pp.237-243
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• 2003

The complicated facilities on the ground have begun to be laid under the ground as increasing emphasis on the beauty of cities due to centralization. But, as the kind of the facilities have been concentrated on the narrow area, accidents occur due to the difficulty of maintenance and the inaccuracy of location information. In this study, first we constructed the field test model to compare with the method of underground probing. So, we could know that the electromagnetic induction method and GPR(Ground Penetration Radar) are useful. It was acquired the position information for the underground facilities using a RTK-GPS. As the result, we have analyzed the accurate position of the underground facility and show the way improving accuracy in detecting and surveying comparing with the traditional surveying method. Also, we hope to contribute the effective maintenance and prevention of disasters to the underground facility as using underground facilities 3D position with Arcview and building the DB of exact depth and underground facilities information system.

• Geomechanics and Engineering
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• v.18 no.5
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• pp.515-525
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• 2019

A karst collapse, as a natural hazard, is totally different to a normal collapse. In recent years, karst collapses have caused substantial economic losses and even threatened human safety. A risk assessment model for karst collapse was developed based on the fuzzy analytic hierarchy process (FAHP) and grey relational analysis (GRA), which is a simple and effective mathematical algorithm. An evaluation index played an important role in the process of completing the risk assessment model. In this study, the proposed model was applied to Jiaobai village in southwest China. First, the main controlling factors were summarized as an evaluation index of the model based on an investigation and statistical analysis of the natural formation law of karst collapse. Second, the FAHP was used to determine the relative weights and GRA was used to calculate the grey relational coefficient among the indices. Finally, the relational sequence of evaluation objects was established by calculating the grey weighted relational degree. According to the maximum relational rule, the greater the relational degree the better the relational degree with the hierarchy set. The results showed that the model accurately simulated the field condition. It is also demonstrated the contribution of various control factors to the process of karst collapse and the degree of collapse in the study area.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.1241-1244
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• 2005

In this case study, the field investigation work on soft soils like a reclamation area with dredged-clay or intertidal mud flat which has not enough strength to resist the load of surveying machines, the amphibious barge(modified AMFIROL) which travels on land and water was adopted to the field investigation work. Despite of slight increase of cost, it was found that the adoption of amphibious barge in field investigation could improve the quality of test results and avoid the waste of time and some effort.

• Journal of Cadastre & Land InformatiX
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• v.53 no.1
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• pp.5-20
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• 2023

The government is operating a course evaluation-type qualification system for the purpose of overcoming the limitations of the test-type qualification system and cultivating talents with practical skills applicable to related industries. However, there is a part that does not match the purpose of the course evaluation qualification system by educating competency units in the field of surveying rather than the field of cadastral field in the education and training course of the course evaluation qualification. Therefore, this study closely analyzed the course evaluation qualification system in the cadastral field and suggested improvement plans accordingly. First, NCS in the cadastral field has not been supplemented or developed since its development in 2014, and there are many parts that do not conform to the current laws, so supplementary development is necessary. Second, It was proposed to improve the optional competency unit in the field of surveying to the NCS competency unit in the cadastral field. In addition, if the 12 competency units of the current NCS in the cadastral field are designated as essential competency units and education and training are operated, it will be possible to foster working-level talents with sufficient competency at the cadastral engineer level. However, for practical system operation and application, supplementation and development of NCS in the cadastral field, which is used for education and training of the course evaluation qualification system, must be preceded.

• Earthquakes and Structures
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• v.18 no.3
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• pp.391-405
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• 2020

The use of passive energy dissipation devices has been widely used in the construction industry to minimize the probability of damage occurred under intense ground motion. In this study, collapse margin ratio (CMR) and fragility curves are the main parameters in the assessment to characterize the collapse safety of the structures. The assessment is done on three types of RC frame structures, incorporating three types of dampers, viscoelastic, friction, and BRB dampers. The Incremental dynamic analyses (IDA) were performed by simulating an array of 20 strong ground motion (SGM) records considering both far-field and near-field seismic scenarios that were followed by fragility curves. With respect to far-field ground motion records, the CMR values of the selected frames indicate to be higher and reachable to safety margin more than those under near-field ground motion records that introduce a high devastating impact on the structures compared to far-field excitations. This implies that the near field impact affects the ground movements at the site by attenuation the direction and causing high-frequency filtration. Besides that, the results show that the viscoelastic damper gives better performance for the structures in terms of reducing the damages compared to the other energy dissipation devices during earthquakes.