• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.15 no.1
• /
• pp.126-132
• /
• 2011

In the application areas of LBS(Location Based Service) and ITS(Intelligent Transportation System), continuous k-nearest neighbor query(CkNN) which is defined as a query to find the nearest points of interest to all the points on a given path is widely used. It is necessary to acquire results quickly in the above applications and be applicable to spatial network databases. It is also able to cope successfully with frequent updates of POI objects. This paper proposes a new method to search nearest POIs for moving query objects on the spatial networks. The method produces a set of split points and their corresponding k-POIs as results with partial order among k-POIs. The results obtained from experiments with real dataset show that the proposed method outperforms the existing methods. The proposed method achieves very short processing time(15%) compared with the existing method.

• Journal of Korean Society for Geospatial Information Science
• /
• v.9 no.2 s.18
• /
• pp.47-54
• /
• 2001

The aim of this study is to represent the effective method for undertaking cadastral surveying works through analyzing and comparison of the surveying results both Total Station and GPS surveying techniques. in the value of coordinate of land parcels, the surveying results of using Total Station and Real Time Kinematic GPS surveying are compared and anayzed. As a results, each axis X and Y differences are ${\Delta}X=0.02m\;and\;{\Delta}Y=0.02$. Therefore the latter surveying method is available to use for production of numerical casdastral map at a large scale and for field surveying in farmland adjustment area. Furthermore travers surveying is not needed to be done when horizontal position of the boundary of a land parcel is determined by the method of RTK. It is recognized as a effective and efficient method in rapaid, accurate and economical aspects.

• Journal of Korean Society for Geospatial Information Science
• /
• v.5 no.1 s.9
• /
• pp.71-80
• /
• 1997

This paper suggests a Map Accuracy Standards by analyzing U.S. National Map Accuracy Standards, by considering korean terrain feature and statistical error theory for paper and digital maps on the scale of 1:50,000. Map accuracy standards require horizontal accuracy to be reported as a circular error with 90% confidence level through Linear Error Probable(LEP) theory and Circular Error Probable(CEP) theory. In order to verify the proposed methodology for positioning accuracy testing, several kinds of test point were selected and tested. These test points were extracted at the centers of roads and bridges, the comers of the independent building, the edges of geographical botany, and the tops of mountains. The positioning accuracy assessment was peformed by comparing the positions of test points in digital maps generated three different sources with those acquired by high accurate GPS surveying. The digital maps were produced from aerial photographs and SPOT satellite image using analytical plotter and 1:50,000 paper map.

• Journal of Korean Society for Geospatial Information Science
• /
• v.3 no.2 s.6
• /
• pp.15-28
• /
• 1995

The GPS positioning involves not only 'natural' errors associated with the satellites position errors, refraction of EM wave in the ionosphere, etc., but also 'artificial' errors associated with the operation of S/A (Selective Availability). In this paper, we present the principles, accuracies and applicabilities of our personal DGPS method, which employs the position-correction method on the GPS positionings data collected at the reference and the remote sites. The essential requirement of our DGPS method is that two GPS receivers should utilize the identical Navstar satellites at the same time. The positioning error (1 drms) of the stand-alone GPS is of an order of a few tens meters, while that of horizontal position by our DGPS method is about 1m and that of vertical position is about 2m We applied out DGPS technique in positioning moving objects, and obtained satisfactory results in tracking the trajectories of a car on the road and the those of drifters in the sea.

• Korean Journal of Remote Sensing
• /
• v.36 no.6_2
• /
• pp.1567-1577
• /
• 2020

Urban land cover classification is role in urban planning and management. So, it's important to improve classification accuracy on urban location. In this paper, machine learning model, Support Vector Machine (SVM) and Artificial Neural Network (ANN) are proposed for urban land cover classification based on high resolution satellite imagery (KOMPSAT-3A). Satellite image was trained based on 25 m rectangle grid to create training data, and training models used for classifying test area. During the validation process, we presented confusion matrix for each result with 250 Ground Truth Points (GTP). Of the four SVM kernels and the two activation functions ANN, the SVM Polynomial kernel model had the highest accuracy of 86%. In the process of comparing the SVM and ANN using GTP, the SVM model was more effective than the ANN model for KOMPSAT-3A classification. Among the four classes (building, road, vegetation, and bare-soil), building class showed the lowest classification accuracy due to the shadow caused by the high rise building.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.20 no.4
• /
• pp.46-56
• /
• 2021

Predicting the incident clearance time is important for eliminating the high transportation costs and congestion from non-repetitive congestion caused by incidents. In this study, the factors influencing the clearance time suitable for domestic road conditions were analyzed, using a training dataset for predicting the incident clearance time using artificial neural networks. In a previous study, the under-prediction problem for high incident clearance time was used. In the present study, over-sampling training data applied using the SMOGN technique was obtained and applied to the model as a solution. As a result, the DNN model applying the SMOGN technique could compensate for the limitations of the previously developed prediction model by predicting the clearance time with the highest accuracy among the models developed in the research process with MAE = 18.3 minutes.

• Journal of the Society of Disaster Information
• /
• v.20 no.3
• /
• pp.654-662
• /
• 2024

Purpose: This study analyzes the current status of open coverage of commercial mobile communication networks, which is an indicator for determining whether the disaster safety communication network call area is secured in mountainous areas, with the aim of more stable operation of the disaster safety communication network. Method: We measured the perceived communication quality on forest roads in a large mountainous area in Samcheok City and compared it with the publicly available commercial cellular network coverage data of three telecommunications companies after spatial overlapping, and found that there was a spatial mismatch between the publicly available commercial cellular network coverage and the perceived communication quality measurement results. Result and Conclusion: Therefore, for the stable operation of the disaster safety communication network in mountainous areas, it is necessary to secure additional PS-LTE mobile base stations and take measures to improve the accuracy of publicly available commercial mobile network coverage.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.26 no.3D
• /
• pp.541-547
• /
• 2006

With the new paradigm of ubiquitous in the developed computing technology, it is urgently necessary to research GIS fields centering around positioning techniques. The intention of this study is to propose implementation methods for integrating topographic and cadastral data. For this purpose an integrated data model is formed to coincide the graphic data of cadastral map with that of topographic map. As a result, the integrated data model could be built by harmonizing cadastral map with topographic map. We suggest data model for connecting with other information systems in the conditions of data uniformity and implementation. This data implementation models suggested in this research can provide a good reference for the future implementation of other systems. This results will be efficiently used as basis for practical use in ubiquitous environments of spatial informations.

• Journal of the Korea Society of Computer and Information
• /
• v.4 no.4
• /
• pp.47-56
• /
• 1999

We design and implement an ORDBMS-based geographic information system for sightseeing information of Chungbuk to verify the performance and applicability of GEUS/XTM ORDBMS. We Acquire the positional coordinates of the boundaries of administrative districts , roads, and railroads, determine the various kinds of information such as the locations of sightseeing sites, lodgings, and so on, design an object-relational schema using OMT, and implement the geographic information system including a database system. Through the examination of selective accessibility on the sightseeing inform ation database by the various queries, we conclude that the ORDBMS is more applicable than other DBMSs in modeling, storing, referring, and managing of non-fixed complex data such as sightseeing information. Therefore, ORDBMSs provide efficient and extensible implementations of databases and information services from various sources for the increasing demand on geographic information service on internet.

• Journal of Korean Society for Geospatial Information Science
• /
• v.23 no.4
• /
• pp.25-33
• /
• 2015

The study of ecosystem assessment(ES) is based on land cover information, and primarily it is performed at the global scale. However, these results as data for decision making have a limitation at the aspects of range and scale to solve the regional issue. Although the Ministry of Environment provides available land cover data at the regional scale, it is also restricted in use due to the intrinsic limitation of on screen digitizing method and temporal and spatial difference. This study of objective is to generate UAV land cover map. In order to classify the imagery, we have performed resampling at 5m resolution using UAV imagery. The results of object-based image segmentation showed that scale 20 and merge 34 were the optimum weight values for UAV imagery. In the case of RapidEye imagery;we found that the weight values;scale 30 and merge 30 were the most appropriate at the level of land cover classes for sub-category. We generated land cover imagery using example-based classification method and analyzed the accuracy using stratified random sampling. The results show that the overall accuracies of RapidEye and UAV classification imagery are each 90% and 91%.