• Journal of Institute of Control, Robotics and Systems
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• v.20 no.3
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• pp.270-276
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• 2014

This survey paper reviews robust control problems in both frequency domain and time domain. Robust control is focused on model uncertainties such as modeling error, system parameter variations, and disturbances. Robust control design problems are discussed according to parameter uncertainty, polytopic uncertainty, and norm-bounded uncertainty. Nowadays, robust control theory is combined with various control theory such as model predictive control, adaptive control, intelligent control, and time delay control.

• Journal of the Korean Chemical Society
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• v.56 no.5
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• pp.548-555
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• 2012

Ultrasonic velocity and density measurements have been undertaken for a number of binary liquid mixtures involving different commercial solvent extractants, LIX reagents. The binary mixtures under investigation have been classified under two categories such as polar-polar, and polar-non-polar types. Different theories and relations such as Schaaff's Collision Factor Theory (CFT), Nomoto's relation (NOM), and Van Dael & Vangeel ideal mixing relation (IMR) have been used to evaluate the velocity theoretically for all these binary systems. The relative merits of afore-mentioned theories and relations compared to experimental values of velocity have been discussed in terms of percentage variations. However, the CFT and Nomoto's relation show better agreement with the experimental findings than the ideal mixing relation for all the systems under investigation.

• Journal of electromagnetic engineering and science
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• v.17 no.4
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• pp.238-240
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• 2017

In this paper, we analyze the radar cross section (RCS) of a battleship equipped with an integrated mast module (IMM). The RCS of a battleship equipped with an IMM is calculated based on physical optics (PO) and the physical theory of diffraction (PTD), and is analyzed in terms of the mast shape, incident angles, and polarization.

• Coupled systems mechanics
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• v.5 no.4
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• pp.329-340
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• 2016

The trigonal shape memory alloys (SMAs) have a great potential to be utilized as the applications with special purposes, such as actuators with high operation frequency. Most studies on the trigonal microstructures typically focus on the well-known classic herringbone pattern, but many other patterns are also possible, such as non-classic herringbone, toothbrush and checkerboard patterns. In the current work, a systematic procedure is developed to find all possible laminate twin microstructures by using geometrically linear compatibility theory. The procedure is verified by SEM images with the information of crystallographic axes of unitcells obtained by EBSD, showing good agreement. Many interesting trigonal R-phase patterns are found in the specimen. Then, their incompatibility are analyzed with nonlinear compatibility theory. The relationship between such incompatibility and the likelihood of occurrence of the microstructures is revealed. The current procedure is rapid, computationally efficient and sufficiently general to allow further extension to other crystal systems and materials.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.10a
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• pp.193-200
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• 2004

In this paper, it is presented a new scheme of adaptive-neuro control system to implement real-time control of robot manipulator. Unlike the well-established theory for the adaptive control of linear systems, there exists relatively little general theory for the adaptive control of nonlinear systems. Adaptive control technique is essential for providing a stable and robust performance for application of robot control. The proposed neuro control algorithm is one of learning a model based error back-propagation scheme using Lyapunov stability analysis method. Through simulation, the proposed adaptive-neuro control scheme is proved to be a efficient control technique for real-time control of robot system using DSPs.

• Structural Engineering and Mechanics
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• v.75 no.2
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• pp.239-246
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• 2020

In this paper, a novel analytical method, Max-Min Approach (MMA), has been presented and applied to consider the nonlinear vibration of dry cask storage systems. The nonlinear governing equation of the structure has been developed using the shell theory. The MMA results are compared with numerical solutions derived by Runge-Kutta's Method (RKM). The results indicate a satisfying agreement between MMA and numerical solutions. Parametric studies have been conducted on the nonlinear frequency of dry casks. The phase-plan of the problem is also presented and discussed. The proposed approach can potentially ca be extended to highly nonlinear problems.

• The Journal of Information Systems
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• v.24 no.3
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• pp.155-169
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• 2015

While information technology(IT) users' behaviors has been considered one of the most important research topics and studied in very many ways, 'non-use' has not been focused as a research topic. However, understanding non-use provides new insights for analyzing and understanding the essential nature of IT uses with wider frames and more qualitative dimension. The objective of this study is to provide some guidelines for studying non-use. For this purpose, the previous studies for non-use were reviewed focusing on resistance, suggested potential research issues and some research methodologies based on grounded theory.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.93-93
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• 2010

In this talk, I will introduce a reactive force field (ReaxFF) molecular dynamics (MD) simulation. In contrast to common MD simulations with empirical FFs, we can predict chemical reactions (bond breaking and formation) in large scale systems with the ReaxFF simulation where all of the ReaxFF parameters are from quantum mechanical calculations such as density functional theory to provide high accuracy. Accordingly, the ReaxFF simulation provides both accuracy of quantum mechanical calculations and description of large scale systems of atomistic simulations at the same time. Here, I will first discuss a theory in the ReaxFF including the differences from other empirical FFs, and then show several applications for studying chemical reactions of SiHx radicals on Si surfaces, which is an important issue in Si process.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.16 no.3
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• pp.157-162
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• 2016

In this paper, a yield prediction model based on relevance vector machine (RVM) and a granular computing model (quotient space theory) is presented. With a granular computing model, massive and complex meteorological data can be analyzed at different layers of different grain sizes, and new meteorological feature data sets can be formed in this way. In order to forecast the crop yield, a grey model is introduced to label the training sample data sets, which also can be used for computing the tendency yield. An RVM algorithm is introduced as the classification model for meteorological data mining. Experiments on data sets from the real world using this model show an advantage in terms of yield prediction compared with other models.

• 한국해양학회지
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• v.14 no.1
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• pp.32-38
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• 1979

The original concept and theory of Shannon's function H=-$\Sigma$(i-1,n)Pi, log$\_$2/Pi and its applicable domains in ecology are discussed. The confusions exist in use and interpretation of this function are due to: 1. Mixing the idea of proper ecological diversity with that of Shannon's information theory. 2. Confusion of physical or thermodynamical systems with ecological systems. 3. Confusion of the system from which one had calculated function H with the system of which function H is interpreted. It's proposed to use function H for the comparison of community's structure and so, for the distinction of community's evolution (succession) steps.