• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.948-953
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• 2001

Nonlinear dynamic equation of a 4-axis rigid rotor supported by two an-isotropic magnetic bearings is derived via Hamilton's principle. It is transformed to a state-space form for the standard Η$_{\infty}$ control problem. we present a robust Η$_{\infty}$ control design methods of continuous and discrete LMI-based approaches and improve performance using loopshaping.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.1710-1715
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• 2000

Estimation of damping ratio for vibration signals measured on the passenger car's seat is useful for the objective evaluation of impact harshness in car. The vibration signal is a transient signal represented by many coupled modes of suspension system. Wavelet transform automatically decouples these modes in the time-frequency domain. Damping ratios for decoupled modes are obtained by logarithmic treatment for the Wavelet transformed signal. The objective evaluation using Wavelet transform has been well corresponded with subjective evaluation done by skilled engineers.

• Journal of applied mathematics & informatics
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• v.16 no.1_2
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• pp.383-405
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• 2004

We study the incomprssible Navier Stokes equations for the flow inside contraction geometry. The governing equations are expressed in the vorticity-stream function formulations. A rectangular computational domain is arised by elliptic grid generation technique. The numerical solution is based on a technique of automatic numerical generation of acurvilinear coordinate system by transforming the governing equation into computational plane. The transformed equations are approximated using central differences and solved simultaneously by successive over relaxation iteration. The time dependent of the vorticity equation solved by using explicit marching procedure. We will apply the technique on several irregular-shapes.

• Journal of the Korean Institute of Telematics and Electronics
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• v.23 no.2
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• pp.131-148
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• 1986

A field ploblem of a grounded dielectric slab covered by a conducting plane with periodecally spaced arbitrary number of slots excited by an aperiodis source is analyzed. The problem is formulated in terms of simultaneous integral equations for unknown electric fields at each slot. A sampling technique is introduced to reduce the system equations to a matrix equation equation involving Green's function matrix. The solution obtained in the form of infinite series is transformed, into a more rapidly convergent one in its final stage. Theoretical results agree closesly with the experimental results.

• Journal of Digital Convergence
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• v.6 no.1
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• pp.1-10
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• 2008

Electronic service delivery is an integral mission that is shouldered upon e-government to carry out. And it also has become an important way of making client-centered administration work more effectively. It is quite convenient from citizens' perspective to utilize public services that are electronically transformed. This study identifies a set of electronic services currently provided by e-government and proposes policy measures for further driving e-government to develop its services in a direction of making people's life more convenient.

• Korean Journal of Computational Design and Engineering
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• v.14 no.4
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• pp.261-270
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• 2009

We can save a lot of efforts and time to perform various kinds of multibody system dynamics simulations if the equations of motion of the multibody system can be formulated automatically. In general, the equations of motion are formulated based on Newton's $2^{nd}$law. And they can be transformed into the equations composed of independent variables by using velocity transformation matrix. In this paper the velocity transformation matrix is derived based on a topological modeling approach which considers the topology and the joint property of the multibody system. This approach is, then, used to formulate the equations of motion automatically and to implement a multibody system dynamics simulation program. To verify the the efficiency and convenience of the program, it is applied to the lifting simulation of a floating crane.

• The Journal of the Korea Contents Association
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• v.4 no.4
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• pp.89-97
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• 2004

Web-Mail Services are implemented with SMTP and POP3 in these days. These web mail services provide not only the basic sending and receiving functions but also additional functions for user. However, the sent and received data are stored in the web mail server. So general web mail users can't process their mail data if they have not access ID for the web mail server. In this paper, we design and implement WMIS (Web Mail Integration System) using XML. In the proposed system, mail data and user's environments in the old web mail system are transformed into XML documents and inserted into database. In order to store XML data into database, we use dynamic document processing method and analyze XML file by record unit. When the users change their mail accounts, they easily can establish the web environments and their mail data. Because the transformed XML document is converted into WML easily, the WMIS can reduce development cost, labors and time.

• Mycobiology
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• v.51 no.3
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• pp.169-177
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• 2023

To further explore the molecular mechanism of triterpenoid biosynthesis and acquire high-value strain of Sanghuangporus baumii, the Agrobacterium tumefaciens-mediated transformation (ATMT) system was studied. The key triterpenoid biosynthesis-associated gene isopentenyl diphosphate isomerase (IDI) was transformed into S. baumii by ATMT system. Then, the qRT-PCR technique was used to analyze gene transcript level, and the widely targeted metabolomics was used to investigate individual triterpenoid content. Total triterpenoid content and anti-oxidant activity were determined by spectrophotometer. In this study, we for the first time established an efficient ATMT system and transferred the IDI gene into S. baumii. Relative to the wild-type (WT) strain, the IDI-transformant (IT) strain showed significantly higher transcript levels of IDI and total triterpenoid content. We then investigated individual triterpenoids in S. baumii, which led to the identification of 10 distinct triterpenoids. The contents of individual triterpenoids produced by the IT2 strain were 1.76-10.03 times higher than those produced by the WT strain. The triterpenoid production showed a significant positive correlation with the IDI gene expression. Besides, IT2 strain showed better anti-oxidant activity. The findings provide valuable information about the biosynthetic pathway of triterpenoids and provide a strategy for cultivating high-value S. baumii strains.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.37 no.11
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• pp.786-795
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• 1988

In this paper a boiler control system simulator is designed and inplemeted in order to evaluate performance of the Fault Tolerant Control System. It simulates a boiler control system of a thermal power plant containtng boiler process, peripheral units and analog controller. The simulator uses a low order linear model for boiler first order models for the peripheral unit. Specifically the model of the analog controller is modularized and transformed to digital form if order to be implemented using a micro-processor board. The experimental results show the usability of the developed simulator for the performance test of the FTCS.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.215-218
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• 2002

A control strategy for a dynamic system under irregular disturbance by using stochastic controller is developed. In order to design stochastic controller, system dynamic model in real domain i transformed dynamic moment equation in stochastic domain by F-P-K approach. A study of real time control technique four stochastic controller is performed in this paper.