• Journal of Institute of Control, Robotics and Systems
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• v.13 no.11
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• pp.1092-1098
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• 2007

A mobile robot localization problem can be classified into following three sub-problems as an observation likelihood model, a motion model and a filtering technique. So far, we have developed the range sensor based, integrated localization scheme, which can be used in human-coexisting real environment such as a science museum and office buildings. From those experiences, we found out that there are several significant issues to be solved. In this paper, we focus on three key issues, and then illustrate our solutions to the presented problems. Three issues are listed as follows: (1) Investigation of design requirements of a desirable observation likelihood model, and performance analysis of our design (2) Performance evaluation of the localization result by computing the matching error (3) The semi-global localization scheme to deal with localization failure due to abrupt wheel slippage In this paper, we show the significance of each concept, developed solutions and the experimental results. Experiments were carried out in a typical modern building environment, and the results clearly show that the proposed solutions are useful to develop practical and integrated localization schemes.

• Journal of the Korean earth science society
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• v.24 no.1
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• pp.7-21
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• 2003

The state-of-art third generation wave prediction model WAM was applied to the Korean seas for a winter monsoon period of January 1997. The wind field used in the present study is the global NSCAT-ERS/NCEP blended winds, which was further interpolated using a bi-cubic spline interpolator to fine grid limited area shallow water regime surrounding the Korean seas. To evaluate and investigate the accuracy of WAM, the hindcasted wave heights are compared with observed data from two shallow water buoys off Chil-Bal and Duk-Juk. A detailed study has been carried with the various meteorological parameters in observed buoy data and its inter-dependency on model computed wave fields was also investigated. The RMS error between the observation and model computed wave heights results to 0.489 for Chil-Bal and 0.417 for Duk-Juk. A similar comparison between the observation and interpolated winds off Duk-Juk show RMS error of 2.28 which suggest a good estimate for wave modelling studies.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.6
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• pp.988-994
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• 1997

The demands for robotic and automatic system are continually increasing in manufacturing fields. There have been many studies to monitor and predict the system, but they have mainly focused upon measuring cutting force, and current of motor spindle, and upon using acoustic sensor, etc. In this study, digital image of time series sequence was acquired by taking advantage of optical technique. Mean square error was obtained from it and was available for useful observation data. The parameter was estimated using PAA(parameter adaptation algorithm) from observation data. AR(auto regressive) model was selected for system model and fifth order was decided according to parameter estimation. Uncorrelation test was also carried out to verify convergence of parameter. Through the proceedings, it was found that there was a system stability.

• Journal of Astronomy and Space Sciences
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• v.37 no.4
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• pp.229-236
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• 2020

There has been increasing necessity of more precise prediction and measurements of aviation radiation in Korea. For our air crew and passengers' radiation safety, we develop our own radiation prediction model of KREAM. In this paper, we validate the KREAM model based on comparison with Liulin observations. During early three months of this year, we perform total 25 experiments to measure aviation radiation exposure using Liulin-6K in commercial flights. We found that KREAM's result is very well consistent with Liulin observation in general. NAIRAS shows mostly higher results than Liulin observation, while CARI-6M shows generally lower results than the observations. The percent error of KREAM compared with Liulin observation is 10.95%. In contrast, the error for NAIRAS is 43.38% and 22.03% for CARI-6M. We found that the increase of the altitude might cause sudden increase in radiation exposure, especially for the polar route. As more comprehensive and complete analysis is required to validate KREAM's reliability to use for the public service, we plan to expand these radiation measurements with Liulin and Tissue Equivalent Proportional Counter (TEPC) in the near future.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2003.10a
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• pp.75-80
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• 2003

Most of the control point surveying use a triangulation point and a bench mark with Total Station and Level. nowadays, the research is being accomplished for practical use of GPS. but In this study the optimum time and the optimum occupation time are analyzed, so as to examine possibility of the control point surveying that use GPS continuous station data of National Geography Institute. Also, The efficient surveying methods that compare the result of data that processed using broadcast ephemeris with the result of data that processed using precise ephemeris. As a result of that, Error feature analysis of the control point surveying in connection with GPS continuous observation will provide us estimation of errors and efficient topography information acquisition

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2006.04a
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• pp.133-138
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• 2006

Currently high resolution satellite imagery has been used in lots of fields of terrain analysis, ocean development, change detection, cartography, classification, environmental monitoring, earth resource observation, meteorological observation as well as military The accuracy of the 3-D modeling of SPOT-5 stereopair images using these ground control points is about 5m in planimetric distance error and about 2m in height error. This study demonstrates the available ground control points for North Korea, of which accuracy is as good as to generate the digital map at the scale of 1:25,000.

• Proceedings of the KIEE Conference
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• 2003.07d
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• pp.2046-2048
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• 2003

In this paper, a neural disturbance observer(NDO) is developed and its application to the control of a nonlinear system with the internal and/or external disturbances is presented. To construct the NDO, a parameter tuning method is proposed and shown to be useful in adjusting the parameters of the NDO. The tuning method employes the disturbance observation error to guarantee that the NDO monitors unknown disturbances. Each of the nodes of the hidden layer in the NDO network is a radial basis function(RBF). In addition, the relationships between the suggested NDO-based control and the conventional adaptive controls reported in the previous literatures are discussed. And it is shown in a rigorous manner that the disturbance observation error converges to a region of which size can be kept arbitrarily small. Finally, an example and some computer simulation results are presented to illustrate the effectiveness and the applicability of the NDO.

• Journal of Satellite, Information and Communications
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• v.5 no.1
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• pp.75-79
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• 2010

Satellite structure is distorted by thermal load in orbit. The structural distortion induces the pointing errors of observation unit that is difference between initial pointing direction at ground integration and at in-orbit. In that case, satellite is not able to point along required direction. As observation capability becomes higher, structural distortion due to thermal load should be smaller to achieve successful mission. In this paper, the method to predict pointing error and results are described.

• Smart Media Journal
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• v.5 no.1
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• pp.9-14
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• 2016

Although the ocean observation and exploration equipment is necessary for the oceanographical observation and strengthening influence of the nation and the resource preemption, it depended on the oversees adoption rather than the domestic development. The MBESs were developed for seabed topography, sedimentary distribution information and underwater objects exploration, but there is no domestic production. So in this research we try the localization of the marine acoustic sounder. Especially about correcting the error occurred on the hardware, we confirmed it on software.

• International conference on construction engineering and project management
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• 2005.10a
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• pp.1042-1047
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• 2005

A web-based camera (webcam) is expected to enhance construction operation monitoring. However, webcams are often installed outside a building because their mobility is limited by cable wiring, which makes it difficult to monitor construction operations inside the building. If a webcam is integrated with emerging wireless communication technologies, construction professionals may be able to monitor interior construction operations using webcams without getting network cables wired on a congested and dynamic construction job site. However, one may concern that wireless communication may not be fast enough to transport all webcam images seamlessly. This paper presents an investigation as to the observation error of webcam images when a limited amount of images are delivered.