• Journal of Electrical Engineering and Technology
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• v.12 no.3
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• pp.1299-1306
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• 2017

This paper presents a boundary tracking control of an agent. To this end, it is shown that the boundary tracking problem can be reformulated into a robust control of uncertain double integrator first. Then, a disturbance observer (DOB) based control is proposed solving the robust control problem. Unlike the existing results in the literature, the proposed DOB based control requires only the local position measurement of the boundary (not the gradient information). The performance of the proposed control is demonstrated for two cases: the measurement of the boundary is given in a continuous or discrete manner. Finally, it is shown that the proposed control can be used for environmental monitoring as well by showing that the agent follows a level curve of real environmental monitoring data.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.2
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• pp.69-75
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• 2004

In this paper, we propose the shape of extremely small thrust VCM for application of the Nanoindenter, which enables control of very small force and displacement. We performed optimization of the VCM shape using conjugated gradient method. And the purposes of optimization are the minimization of the permanent magnet size for the efficient systems, minimization of deviation of flux density from the air gap for operate on regular thrust and a linearization of thrust for a good control characteristic. The finite element method is used for characteristic analysis. The node moving method is used to redundant changes of design variables. As a result, the VCM produces a yew small force by the difference of flux density of lower part from higher one. Also, in a wide range of current (0［A］-1［A］), the VCM produces linear driving thrust by saturating the magnetic circuit path and operate on regular thrust by minimizing deviation of flux density of the air gap.

• Journal of Information Processing Systems
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• v.16 no.1
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• pp.145-154
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• 2020

Maximum likelihood (ML) is the best estimator asymptotically as the number of training samples approaches infinity. This paper deduces an adaptive algorithm for blind signal processing problem based on gradient optimization criterion. A parametric density model is introduced through a parameterized generalized distribution family in ML framework. After specifying a limited number of parameters, the density of specific original signal can be approximated automatically by the constructed density function. Consequently, signal separation can be conducted without any prior information about the probability density of the desired original signal. Simulations on classical biomedical signals confirm the performance of the deduced technique.

• Proceedings of the Korean Printing Society Conference
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• 2000.04a
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• pp.17-24
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• 2000

The Joint Photographic Experts Group (JPEG) is a standara still-image compression technique, established by the International for Standardization (ISO) and International Telecommunication Standardization Sector (ITUT). The standard is intended to be utilized in the various kinds of color still imaging systems as a standard color image coding format. Because JPEG is a lossy compression, the decompressed image pixel values are nto the same as values before compression. Image of JPEG compression is often made to JPEG recompression at saving to apply JPEG compression of color image. In general, JPEG is a lossy compression and compression image is predicted to be varied image quality according to recompressed Q-factor. Various distortions of JPEG compression and JPEG recompression has been reported in previous paper. In this paper, we compress four difference color samples (photo image, gradient image, vector drawing image, text image) according to various Q-factor, and then compressed images are recompressed according to various Q-factor once again. As the results, we inspect variation of quality and file size of recompressed color image, and ensure the optimum recompression factor.

• Journal of the Korean Institute of Landscape Architecture
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• v.25 no.1
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• pp.124-134
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• 1997

The primary purpose of this research is to scientifically investigate visual structure of Korean feng-shui at the level of village settlement. This study deals with Hahoi and Yangdong villages of which feng-shui is regarded highly fit to traditional feng-shui principles. Methodologically this research utilizes analytical tools of geographical information systems and statistical analysis methods, Visual structures of the villages'feng-shui are analyzed in terms of elevation, orientation, gradient of slope and relative dominance of visibility of major hills. A mathematical model is suggested to quantify facets of the villages'lung-shui with reference to slope trends. The quantitative analysis results indicate that both villages have good feng-shui. Hahoi village has an excellent feng-shui attributable to a near perfect harmony between water and terrain while Yangdong village has an effective feng-shui facet for conserving energy in terms of microclimate. Principles of fang-shui have potentials to be developed as a holistic planning and design language. Further in-depth research on feng-shui needed to accomplish this goal.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.543-545
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• 2003

In this study, the authors evaluate the suitability of the candidate routes selected by the route selection method, which is developed by the authors, by combination of Geographic Information Systems (GIS) and Analytic Hierarchy Process. To evaluate the suitability of the candidate routes, from the viewpoint of the residents, we have considered element factors such as, population, household, aging situation, elevation, gradient, housing density and the Control Point. The results of this study are expected to assess the suitability of the candidate routes of the hillside transportation for the residents and examine the application limit of the route selection method.

• Proceedings of the Korea Water Resources Association Conference
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• 2000.05a
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• pp.28-36
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• 2000

A TIN, Triangulated Irregular Network, based topographic modeling method and a distributed rainfall-runoff model using the topographic representation is presented. In the TIN based topographic representation, a watershed basin is modeled as a set of contiguous non-overlapping triangular facets: the watershed basin is subdivided according to streamlines to deal with water movement one-dimensionally; and each partitioned catchment is approximated to a slope element having a quasi-three-dimensional shape by using cubic spline functions. On an approximated slope element, water movement is represented by combined surface-subsurface kinematic wave equations considering a change of slope gradient and slope width. By using the distributed rainfall-runoff model, the effects of spatial variability of soil properties on runoff response are examined.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.43.1-43
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• 2001

We propose two control methods of the Lyapunov exponents for Jordan-type recurrent neural networks. Both the two methods are formulated by a gradient-based learning method. The first method is derived strictly from the definition of the Lyapunov exponents that are represented by the state transition of the recurrent networks. The first method can control the complete set of the exponents, called the Lyapunov spectrum, however, it is computationally expensive because of its inherent recursive way to calculate the changes of the network parameters. Also this recursive calculation causes an unstable control when, at least, one of the exponents is positive, such as the largest Lyapunov exponent in the recurrent networks with chaotic dynamics. To improve stability in the chaotic situation, we propose a non recursive formulation by approximating ...

• Bulletin of the Korean Chemical Society
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• v.14 no.6
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• pp.692-696
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• 1993

Prediction of retention times in transition metal-mandelate and transition metal-tartrate complex systems were studied on the cation exchanger. Plots of k' vs [mandelate] and k' vs [tartrate] were obtained under the condition of a constant competing cation concentration. The equation to predict the retention time of transition metal ion was derived from the ion exchange equilibria. Individual capacity factors (${k_1}',\;{k_2}'$) and stability constants ($K_1,\;K_2$) of the complexes were calculated from the non-linear least square method. Good resolution of the transition metals was predicted by the stepwise equation in the gradient method. The values of retention times from the calculation and the experiment agreed well each other.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1-9
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• 2008

A wide metropolitan railway and a metropolitan railway in metropolitan area are transportation systems to cope with possible large demand and are under construction continually. A wide metropolitan railway and a metropolitan railway in metropolitan area are running with low speed because it is difficult to improve train speed according to short distances between stations and topography. There is a few study on improving commercial speed on the existing wide metropolitan railway and metropolitan railway in metropolitan area, but there is no study on a new wide metropolitan railway. This study present speed-up scheme of the Sosa-Wonsi line by enlarging the curve radius, reducing the horizontal steep gradient, reducing the stopping time, speeding up at underground section, and installing the PSD, etc. This scheme is evaluated using the simulation technique.