• Proceedings of the Korean Information Science Society Conference
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• 2001.04a
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• pp.76-78
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• 2001

Secure Lambda calculus(SLam)는 정보 보안을 보장해주는 언어이나, Continuation Passing Style(CPS) 변환 후에는 안전성 분석의 정확도가 떨어진다. CPS의 논리적인 성질(ordered linearity)을 반영하여 변환 후에도 정확도가 떨어지지 않는 타입 시스템을 고안하고 무간섭성을 증명하였다. 함수형 SLam 언어에서 정확도가 떨어지는 경우는 앞으로 계산할 값의 인자가 쓰이지 않는 경우임을 밝혀내었다.

• Journal of the Korean Institute of Telematics and Electronics
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• v.23 no.4
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• pp.571-577
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• 1986

In this paper, we have investigated pole-zero shifting due to variable stopband frequency Ws and passband ripple Ap of elliptic function filters. Also we have studied the phase, group-delay, unit step response and impulse response of elliptic filters. We show that in the passband the phase linearity improves as Ws increases, and eventually it approaches that of a chebyshev function filter.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.5B no.2
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• pp.129-136
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• 2005

This paper presents a design strategy of SPOKE type BLDC motors considering an irreversible demagnetization of a permanent magnet (PM). So the irreversible demagnetization characteristic of the motor is analyzed by rotor structure. The instantaneous currents in either starting or lock rotor condition, which are calculated from the current dynamic analysis, are applied to the analysis of the irreversible demagnetization field by FEM. In irreversible demagnetization analysis by FEM, the variation of residual flux density in PM is analyzed using the non-linearity of magnetic core on B-H plan. The analysis results are compared to several rotor structures and used for optimize the rotor structure.

• Journal of the Korean Society for Railway
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• v.5 no.1
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• pp.40-47
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• 2002

In this study, and analytical method for ride sensitivity analysis of a train with non-linear suspension elements are proposed. Non-linear characteristics of springs and dampers for primary and secondary suspensions of a train are parameterized using polynomial interpolation. Vertical dynamic model of a three-body train running on straight rail with the predetermined roughness expressed in terms of spectral density function is set up and its equations of motion for ride analysis are derived. Using the direct differentiation method, sensitivity equations of the vertical dynamic model with respect to design parameters associated with non-linearity of suspensions are obtained. Based on the sensitivity analysis, improvement of ride is achieved by varying appropriate suspension parameters.

• YAKHAK HOEJI
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• v.47 no.4
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• pp.195-199
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• 2003

An analysis method for the determination of methylendedioxymethamphetamine (MDMA) and its metabolite methylendedioxymethamphetamine (MDA) in hair by gas chromatography/mass spectrometry was proposed. For MDMA and MDA analysis, hair samples were incubated in MeOH (1％ HCl), derivatized with trifluoroacetic anhydride and assayed by GC/MS. Hair of 18 subjects for drug abuse was analyzed for MDMA and MDA. Calibration curves for the determination of MDMA and MDA in hair showed a good linearity at a concentration range from 0.5 ng to 250 ng ($r^2$=0.999) The extraction recovery was determined from hair blanks at 50, 100 ng. The percentage of recovery were found to be 96.08∼103.48 with CV value of 1.62∼3.89. The concentrations of MDMA and MDA ranged 1.14∼38.06 ng/mg and 0.07∼3.91 ng/mg, respectively in 18 hair samples from MDMA abusers. The ratio of MDMA to MDA ranged from 9.65∼28.46 in all specimen. Hair analysis for MDMA is a useful method for identification of long-term drug abuser.

• Journal of Korean Association for Spatial Structures
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• v.6 no.4 s.22
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• pp.45-52
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• 2006

FRP laminated plates have strong material-nonlinearity. Through vibration Analysis of FRP laminated plates, the result of nonlinearity analysis is compared with the result of linearity analysis according to stacking angle and squency. This study is a fundamental study about displacement in nonlinearity dynamic behavior of FRP laminated plates.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2005.04a
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• pp.473-480
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• 2005

Geometrical non-linearity due to the flexibility of cables must be considered efficiently in the dynamic analysis of cable structures. In this paper, formulation of tangent stiffness matrix of elastic catenary cable is derived by using relative nodal displacements, self-weight and unstressed cable length. Free vibration analysis of simply supported cable using elastic catenary cable elements is conducted and compared with that using truss elements. The result shows that elastic catenary cable elements are more compatible than truss elements in the case of analysis of cable structures. Furthermore, the characteristic of dynamic behaviors of cable structures by temporary unstability phenomenon is confirmed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1996.04a
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• pp.86-91
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• 1996

In this study, the modal analysis is adopted for the investigation of vibratory characteristics of a rolling stock. A governing equation for this system is deverived on a condition that the rolling stock is in proportional viscous damping and proportional hysteretic damping. By applying this method a computational modal analysis software is developed. The validity and reliability of this method is verified by comparing the results for the above case and with those of a system having proportional viscous damping and a system having general viscous damping. A system that has non-linearity, an error from the calculation may occur in the analysis. In this case, we applied the piecewise linear method to estimate the modal parameters.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.6 s.183
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• pp.128-135
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• 2006

Rational dynamic modeling and analysis method f3r complex structures are studied with special attention to slide way joints. For modeling of slide way joints, a general modeling technique is used by using the influence coefficients method which is applied to the conversion of detailed finite element model to the equivalent reduced joint model. The theoretical part of this method is illustrated and the method is applied to the structure with slide way joint. In this method, the non-linearity of the contact surfaces is considered within a proper range and the boundary effect of the joint model could be eliminated. The proposed method was applied to finite element modal analysis of a clamp jointed cantilever beam and slide way joints of the vertical type lathe. The method can also be used to other kinds of joint modeling. The results of these analysis were compared with those of Yoshimura models and rigid joint models, which demonstrated the practical applicability of the proposed method.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.669-671
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• 2001

This paper describes the operating characteristic analysis of PM-type magnetic circuit breaker for electromagnetic field, electric circuit and mechanical motion problems. Transient calculations are based upon the magnetic equivalent circuit analysis including non-linearity of materials and using iteration routines. The analysis results of this magnetic equivalent circuit are compared with those of FEM.