• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1383-1384
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• 2015

In this paper, a dynamics model embedded navigation filter is newly suggested for underwater autonomous systems without position or attitude aid. In order to ensure the observability on the INS errors, the hydrodynamics of the underwater vehicle is incorporated with the INS attitude error. This approach allows us to estimate and compensate the INS errors in spite of using external velocity sensor. Through the simulation, the performance and effectiveness of the proposed scheme are demonstrated.

• The Journal of Korea Robotics Society
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• v.9 no.2
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• pp.96-103
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• 2014

Global localization is one of the essential issues for mobile robot navigation. In this study, an indoor global localization method is proposed which uses a Kinect sensor and a monocular upward-looking camera. The proposed method generates an environment map which consists of a grid map, a ceiling feature map from the upward-looking camera, and a spatial feature map obtained from the Kinect sensor. The method selects robot pose candidates using the spatial feature map and updates sample poses by particle filter based on the grid map. Localization success is determined by calculating the matching error from the ceiling feature map. In various experiments, the proposed method achieved a position accuracy of 0.12m and a position update speed of 10.4s, which is robust enough for real-world applications.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.835-840
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• 2001

The new approach is a kind method of restoring temporary defect. Here, it is important for the defect not to occur problems of both local effect and global system. A basic concept is that it measures remaining prestress of PSC structures during the defect is restored. This study suggested new approach for measurement of remaining prestress. Two important results are obtained. First, safety problems, local stress concentration and global system, are very satisfied. Second, measurement value exists within error bound $\pm$ 1% in comparison with known value.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10b
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• pp.700-702
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• 2004

A local-step optimization method is proposed to supplement the global-step optimization methods which adopt online update mode of internal weights and error energy as stop criterion in learning of multilayer perceptrons (MLPs). This optimization method is applied to the standard online error backpropagation(EBP) and the performance is evaluated for a speaker verification system.

• Bulletin of the Korean Mathematical Society
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• v.52 no.5
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• pp.1445-1465
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• 2015

In this paper, the long time behavior of the convective Cahn-Hilliard equation in two dimensions is considered, semidiscrete and completely discrete spectral approximations are constructed, error estimates of optimal order that hold uniformly on the unbounded time interval $0{\leq}t<{\infty}$ are obtained.

• Proceedings of the KIEE Conference
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• 1992.07a
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• pp.377-380
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• 1992

This paper proposes a novel direct adaptive pole placement control algorithm which can be applied to continuous time nonminimum phase systems. The algorithm is based on Lyapunov's direct method. By introducing an auxiliary signal, a minimal error model is constructed in state space. Using the error model an estimation law is obtained via Lyapunov's second stability theorem. The global stability of the overall system is established.

• Journal of applied mathematics & informatics
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• v.5 no.3
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• pp.669-690
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• 1998

In this paper we develop a new theory of adjoint and symmetric method in the class of general implicit one-step fixed-stepsize methods. These methods arise from simple and natral def-initions of the concepts of symmetry and adjointness that provide a fruitful basis for analysis. We prove a number of theorems for meth-ods having these properties and show in particular that only the symmetric methods possess a quadratic asymptotic expansion of the global error. In addition we give a very simple test to identify the symmetric methods in practice.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2010.04a
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• pp.147-150
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• 2010

Ionopheric deley is the largest error sources in GNSS positining. The single frequency receiver user needs an ionospheric model like the Klobuchar model or NeQuick model to eliminate the ionospheric error. In this study we estimated VTEC(Vertical Total Electron Content) over DAEJ station using the two models in each season. We compared the results with Global Ionosphere Maps and International Reference Ionosphere model predictions. As a result, the NeQuick model was more accurate than Klobuchar model.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.32 no.6
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• pp.219-224
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• 1983

The problem of model reference adaptive control for the discrete time system is considered and the global stability of the overall system is shown. It extends the results of Kreisselmeier's to more general reference models and the method presented here makes the output error and controller parameter error converge to zero. The scheme presented in this paper is simulated and the simulation gives the expected results.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.33 no.2
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• pp.56-61
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• 1984

The problem of model reference adaptive control for the discrete time system is considered and the global stability of the overall system is shown. It extends the results of Choi's to the plants and models whose transfer functions have arbitrary gains and the method presented here makes the output error and the conftroller parameter error converge to zero. The scheme presented in this paper is simulated and gives good results.