• Transactions of the Korean Society of Automotive Engineers
• /
• v.5 no.6
• /
• pp.202-214
• /
• 1997

In automotive industries, one of major issues is the shifting shock, which is brought out when two clutches are engaged in an automatic transmission. The engagement and disengagement if two clutches means the variation of the D.O.F(degree of freedom) of system. Therefore to analyze the shifting performance, the variation of D.O.F should be considered in detail. Generally, the programs for analyzing the shifting transients have been developed as the problem-dependent codes because the artificial maris were usually used to indicate the change of shifting phase. To develop a software applicable to a general mechanism of transmissions, a self-determining algorithm of D.O.F must be applied. Through the experiences for the last several years, a generalized analysis software of shifting mechanism(so called by POTAS-MSM Version 2.0) has been developed. In this study, some major ideas of the software and the concept for the analysis of shifting characteristics are presented. In addition to that, this paper shows how to self -determine D.O.F of he multi-slipping systems using the stick-slip criterion on a single slipping mechanism. By using this software, the shifting characteristics of a vehicle are analyzed and compared with the experimental results.

• Journal of Navigation and Port Research
• /
• v.28 no.4
• /
• pp.277-284
• /
• 2004

This paper tries to draw some implications for Korean seaports in terms of management and development of ports with respect to attracting more transshipment container cargoes. For this the results of the Origin-Destination(O-D) analysis between major Korean ports and top 20 Chinese ports were presented. They also contained the O-D analysis between Chinese major ports and their inland hinterlands.

• Journal of Magnetics
• /
• v.15 no.1
• /
• pp.36-39
• /
• 2010

The multi-degrees of freedom surface permanent-magnet motor (Multi-D.O.F. SPM) has several degrees of freedom operations that are defined as the "roll", "yaw", and "pitch". Normally, the torque that is generated to rotate a rotor includes ripples. The analysis of the torque ripples is important for improving motor performance. In terms of the electric analysis, torque ripple occurs as a result of many factors, including the rotor and stator structures, the distribution of the air-gap flux density, and the waveform of the current in the coils. In particular, the torque ripple is an important factor in the stable operation of the Multi-D.O.F. SPM. Therefore, in this work, the torque ripple was analyzed using various types of magnetization for the permanent magnet. An improved model was proposed for the Multi-D.O.F. SPM based on this analysis.

• Korean Journal of Pharmacognosy
• /
• v.51 no.1
• /
• pp.55-64
• /
• 2020

In this study, 15 compounds were elucidated from the hot-water extract of Perillae Folium. Fifteen isolates were determined to be protocatechuic acid (1), caffeic acid (2), (R)-rosmarinic acid (3), (S)-shisoflavanone A (4), luteolin-7-O-β-D-glucuronopyranoside (5), scutellarein-7-O-β-D-glucuronopyranoside (6), apigenin-7-O-β-D-glucuronopyranosyl(1→2)-O-β-D-glucuronopyranoside (7), luteolin-7-O-β-D-glucuronopyranosyl(1→2)-O-β-D-glucuronopyranoside (8), kelampayoside A (9), trans-N-feruloyloctopamine (10), 3-(4-hydroxy-3-methoxyphenyl)-N-[2-(4-hydroxyphenyl)-2-methoxyethyl]acrylamide (11), perilloside C (12), perilloside A (13), (6S,9R)-9-hydroxy-megastigma-4,7-dien-3-one-9-O-β-D-glucopyranoside (14) and (6S,9R)-roseoside (15) through spectroscopic evidences. The HPLC analysis revealed that hot-water extract of Perillae Folium contained caffeic acid, rosmarinic acid and glycosides of apigenin, luteolin and scutellarein as main constituents.

• Natural Product Sciences
• /
• v.24 no.4
• /
• pp.259-265
• /
• 2018

The three flavone glycosides, 4'-O-methylisoscutellarein 7-O-(6'''-O-acetyl)-${\beta}$-D-allopyranosyl(1${\rightarrow}$2)-${\beta}$-D-glucopyranoside (1), isoscutellarein 7-O-(6'''-O-acetyl)-${\beta}$-D-allopyranosyl(1${\rightarrow}$2)-${\beta}$-D-glucopyranoside (3), and isoscutellarein 7-O-${\beta}$-D-allopyranosyl(1${\rightarrow}$2)-${\beta}$-D-glucopyranoside (4) in addition to a flavonol glycoside, kaempferol 3-O-${\beta}$-D-glucopyranoside (astragalin, 2), were isolated from Stachys japonica (Lamiaceae). In cholinesterase inhibition assay, compound 1 significantly inhibited aceylcholinesterase (AChE) and butyrylcholinesterase (BChE) activities ($IC_{50}s$, $39.94{\mu}g/ml$ for AChE and $86.98{\mu}g/ml$ for BChE). The content of isolated compounds were evaluated in this plant extract by HPLC analysis. Our experimental results suggest that the flavonoid glycosides of S. japonica could prevent the memory impairment of Alzheimer's disease.

• Proceedings of the KIEE Conference
• /
• 2002.07c
• /
• pp.1906-1908
• /
• 2002

In general, ZnO lighting arrester are known to exhibit an increases in resistive current with time, the rate of increase being exacerbated with increasing applied voltage. In addition, since the resistive leakage current caused by deterioration of ZnO lighting arrester mainly caused an increase of the third harmonic component, thereby it is possible the arrester degradation diagnosis by measuring the third harmonic component in the total leakage current. So, in this paper, we presents a leakage current measuring and analysis system of 18[kV] ZnO lighting arrester.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1996.04a
• /
• pp.341-345
• /
• 1996

Many mechanical and electrocal systems use the number of motors to make multi degree of freedom motion. One method to reduce the number of motors is suggested by using the 3 D.O.F. motor. The 3 D.O.F. motor has advantages such as downsize, weight reduction, and simplification of the existing 3 D.O.F. systems. In this study, a mathematical model for the 3 D.O.F. motor is suggested and the dynamic equation is derived to analyze the 3 D.O.F. motion. Generallinear control methods are very hard to get the good performance because of the nonlinear terms of each degree of each degree of freedom. To control the motion properly, the nonlinear terms are decoupled using a feedback control law. Nonlinear feedback control law which can arrage the poles arbitrarily is derived. The effects of the gains are examined through computer simulations.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2000.11a
• /
• pp.551-554
• /
• 2000

Alignment system is a system to locate an object to it's accurate position in multi-d.o.f space. According to process of application, it is need to align an object in 3 or 6 d.o.f. space. And alignment system is used in various environments. Especially in PDP application, alignment process is carried out in vaccume environment. In this paper, we developed 3 d.o.f. alignment system for vaccume environment, performed kinematic analysis and improved it's positional accuracy.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2002.05a
• /
• pp.559-562
• /
• 2002

본 논문에서는 최근 제한적으로 사용이 승인된 UWB(초광대역： Ultra-Wideband) 통신을 AWGN 하에서 다중 접속을 고려하지 않은 단일 사용사일 경우로 가정시, M진 값이 변화함에 따른 에러율과 성능 개선 기법으로 BCH를 채용시의 에러율을 비교 분석하였다. 기존에 연구되어 오던 변조로 PAM(Pulse Amplitude Modulation)과 PPM(Pulse Position Modulation)방식을 비교하였으며 에러율 $10^{-6}$을 기준으로 M=2, 4일 경우 PAM이 PPM보다 약 E$_{b}$/N$_{o}$ =3~4［dB］, M=8 이상의 경우 PPM이 약 E$_{b}$/N$_{o}$ =9［dB］, M=16일 경우 약 E$_{b}$/N$_{o}$ =15［dB］정도 성능이 우수하였다. AWGN 채널 하에서 에러 정정 부호인 BCH(15,7)를 도입하였을 경우 에러율 $10^{-6}$을 기준으로 PAM방식은 약 E$_{b}$/N$_{o}$ 가 약 1［dB］, PPM 방식은 M=2, 4일 경우 약 E$_{b}$/N$_{o}$ =1~1.5［dB］정도 개선되었다.

• Natural Product Sciences
• /
• v.18 no.3
• /
• pp.200-203
• /
• 2012

The chromatographic separation of a methanol extract of Prunus mume (Rosaceae) led to the isolation of 5-hydroxymethyl-2-furaldehyde (1), 4-O-caffeoylquinic acid methyl ester (2), prunasin (3), 5-O-caffeoylquinic acid methyl ester (4), benzyl-O-${\beta}$-D-glucopyranoside (5), and liquiritigenin-7-O-${\beta}$-D-glucopyranoside (6). Their structures were determined by 1D, 2D-NMR and MS data analysis as well as by comparison of their data with the published values.