• Journal of Advanced Marine Engineering and Technology
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• v.20 no.2
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• pp.57-62
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• 1996

In order to reject the steady-state tracking error, it is common to introduce integral compensators in servosystems for constant reference signals. However, the mathematical model of the plant is exact and no disturbance input exists, the integral compensation is not necessary. From this point of view, a two-degree-of-freedom(2DOF) servosystem has been proposed, in which the integral compensation is effective only when there is a modeling error or a disturbance input. The present paper considers robust stability of this 2DOF servosystem to the unstructured uncertainty of the controlled plant. A robust stability condition is obtained using Riccati inequality, which is independent of the gain of the integral compensator. An example is presented, which demonstrates that the tracking response of the 2DOF servosystem with uncertainty becomes faster when the integral gain made larger under the robust stability condition.

• Journal of the Society of Naval Architects of Korea
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• v.41 no.4
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• pp.38-44
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• 2004

The motion response analysis of a submerged elliptic cylinder in waves is presented and the elliptic cylinder is a simplification of the section of submarine in this paper. The method is based on boundary integral method and two-dimensional 3 degree motions are calculated in regular harmonic waves. The fully nonlinear free surface boundary condition is assumed in an numerical domain and this solution is matched along an assumed boundary as a linear solution composed of transient Green function, The large amplitude motions of an elliptic cylinder are directly simulated and effects of wave frequency, wave amplitude and the distance from buoyancy center to gravity center are discussed.

• Journal of the Korean Ceramic Society
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• v.31 no.4
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• pp.457-463
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• 1994

The growth condition of highly oriented textured diamond film on a (100) Si substrate was investigated as a function of texture orientation. The growth process consisted of biased enhanced nucleation (BEN) and texture growth. The substrate was under the plasma of 6% CH4-94% H2 with negative bias of 200V during the BEN which grounded during the texture growth. The texture orintation changed from <100> to <110> by increasing substrate temperature. The nearly perfect match between textured diamond grains and the Si substrate could be obtained under the condition of <100> texture. The degree of tilt mismatch increased with the increase of deviation of texture orientation from <100>. The degree of twist mismatch appeared to increase abruptly beyond the critical deviation of texture orientation from <100> because the nuclei having the same orientation as the substrate were no more preferred grains for texture formation.

• Proceedings of the KOSOMBE Conference
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• v.1993 no.11
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• pp.23-26
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• 1993

In MR functional imaging, it is shown that the signal change during photic activation is composed of two terms, i.e. the inflow effect and the susceptibility effect. Relatively the inflow effect affects the data obtained by CGE on the condition of short $T_E$(15ms) and large $\alpha$(90degree). The susceptibility effect, however, mainly contributes to the data on the condition of large $T_E$(35ms) and small $\alpha$(30degree). In this apper, we will discriminate the susceptibility effect for the intermingled data affected both flow effect and susceptibility effect. Finally susceptibility only functional imaging is proposed by using TRFGE.

• Journal of Electrical Engineering and Technology
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• v.6 no.5
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• pp.706-712
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• 2011

Necessary and sufficient conditions for the existence of diagonal, block-diagonal, and triangular decoupling controllers in linear multivariable systems for the most general setting are presented. The plant model in this study is sufficiently general to accommodate non-square plant and non-unity feedback cases with one-degree-of-freedom (1DOF) or two-degree-of-freedom (2DOF) controller configuration. The existence condition is described in terms of rank conditions on the coefficient matrices in partial fraction expansions.

• Journal of the Korean Mathematical Society
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• v.61 no.2
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• pp.279-291
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• 2024

In this paper, we investigate a few strategies to construct Ulrich bundles of small ranks over smooth fourfolds in ℙ⁵, with a focus on the case of special quartic fourfolds. First, we give a necessary condition for Ulrich bundles over a very general quartic fourfold in terms of the rank and the Chern classes. Second, we give an equivalent condition for Pfaffian fourfolds in every degree in terms of arithmetically Gorenstein surfaces therein. Finally, we design a computer-based experiment to look for Ulrich bundles of small rank over special quartic fourfolds via deformation theory. This experiment gives a construction of numerically Ulrich sheaf of rank 4 over a random quartic fourfold containing a del Pezzo surface of degree 5.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.377-378
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• 2002

In many dynamic systems, unwanted vibrations which may arise during operation of machines are costly in terms of reduction of performance and service life. Sometimes these risky oscillations endanger equipment and personnel. When hydraulic telescopic booms taken large mass are driven at slow speeds between the two pads, unstable oscillations occur through the stick-slip at the sliding parts and become more severe and saw-toothed. This paper supposes few models for the telescopic boom in the multi-degree of freedom system, and attempts a theoretical approach for the numerical analysis in its stick-slip condition, It was verified that this theoretical approach has an effect on estimate of stick-slip in the one-degree as well as multi-degree of freedom system.

• Journal of Electrical Engineering and Technology
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• v.6 no.6
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• pp.874-882
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• 2011

The decoupling design for the one-degree-of-freedom controller system is treated within the $H_{\infty}$ framework. In the present study, we demonstrate that the $H_{\infty}$ performance problem in the decoupling design is reduced into interpolation problems on scalar functions. To guarantee the properness of decoupling controllers and the overall transfer matrix, the relative degree conditions on the interpolating scalar functions are derived. To find the interpolating functions with relative degree constraints, Nevanlinna-Pick algorithm with starting function constraint is utilized in the present study. An illustrative example is given to provide details regarding the solution.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.32-36
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• 2001

Recently, reaction injection molding has been used broadly for rapid prototyping, because of its convenience and versatility. Since the properties of molded products are dependent on the process variables and the production is very short(less than 2minutes), the control of process variables is important. Generally, the two significant process variables are degree of cure and temperature of the reactants. In this paper, the relation between the degree of cure and the temperature of reactants was investigated to find the optimal curing condition of reaction injection molding for rapid prototyping. The degree of cure during reaction injection molding was measured by the Lacomtech sensor and dielectrometry equipment employing Wheatstone bridge type circuit.

• Journal of the Korean Society of Clothing and Textiles
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• v.22 no.7
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• pp.882-891
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• 1998

This study purported to analyze the condition of the degree standardization and types of global ads. in the multinational fashion brand corporations. The analyzed ads. were sampled from monthly magazines on same seasons in 1997. This study was done by means of checklists were modified other researcher's research measurments. Researcher counted of advertising message. Zero point meant perfect stan-dardization and 13 points meant perfect non-standardization. The types of advertising appeal were analyzed according to constituent unit's expression types. The results of the study proved that the degree of standardization was considerably high, which means that the multinational fashion brand corporations used the standardization strategy. In particular, the degree of standardization in sports wear and casual wear ads. was low compared with the degree of standardization in the other ads. Most of the global fashion ads. were composed of illustrations only. Besides, emotional appeal type was usually used in glabal fashion ads.