• Journal of KSNVE
• /
• v.5 no.3
• /
• pp.385-394
• /
• 1995

Recently, since robot manipulator becomes faster and lighter, its link is no longer regarded as rigid body, and robot controller which only controls robot position cannot reduce vibration of the flexible link. Therefore vibration control is needed in robot manipulator control in addition to position control. In the case that tip mass changes when robot manipulator in working, it is clear that the efficiency of the vibration/position controller designed for the fixed system goes down. In this paper, the system with time varying parameters, adaptive control theory is adopted which estimates parameters changed by the variation of the tip mass and re-calculates the gain of the controller. Validify of the proposed adaptive controller and capability of the estimator are evaluated by computer simulations and experiments. Comparison results of the optimal controller for the fixed system and proposed adaptive controller and carried out.

• Journal of Astronomy and Space Sciences
• /
• v.2 no.1
• /
• pp.35-45
• /
• 1985

Standardized B and V photoelectric light curves of Algol are made with the obsevations obtained during 1982-84 with the 40-cm and the 61-cm reflectors of Yonsei University Observatory. These light curves show asymmetry between ascending and descending shoulders. The ascending shoulder is 0.02 mag brighter than descending shoulder in V light curve and 0.03mag in B light curve. These asymmetric light crves are interpreted as the result of inhomogeneous energy distribution on the surface of one star of the eclipsing pair rather than the result of gaseous stream flowing from KOIV to B8V star. The 180-year periodicity, so called great inequality, are most likely the result proposed by Kim et al.(1983) that the abrupt and discrete mass losses of cooler component may be the cause of this orbital change. The amount of mass loss deduced from these discrete period changes turned out to be of the order of $10^{-6}$ - $10^{-5}M_\odot$.

• Proceedings of the Korea Contents Association Conference
• /
• 2003.11a
• /
• pp.454-459
• /
• 2003

Nowadays comic strip(or comics) has surpassed its limits as a role of humor and amusement. And it has firmly established its role as a kind of public information and mass media. Furthermore it is used as materials for effective learning and human nature education to prevent the problems caused by rapid changes, and means to lessen or relax stress. The author will examine the specific ability, characteristics and potential of comics in this modem society. This paper will discuss the results caused by comic strip and show the possibility that comics can achieve the aim as a mass media

• Journal of Korean Academy of Oral and Maxillofacial Radiology
• /
• v.24 no.1
• /
• pp.151-159
• /
• 1994

Authors experienced a case of intermediate grade mucoepidermoid carcinoma in 29-year-old female. The origin of this tumor might be mucus secreting cells of palatal mucous gland. The characteristic features were as follows: 1. In clinical examination, exopytic mass was observed in left hard palate and similar to pleomorphic adenoma. 2. In radiographic findings, destructive changes of left hard palate, nasal septum, nasal inferior turbinate and floor of maxillary sinus and soft tissue mass were observed. 3. Histopathologically, mucus-secreting cells, epidermoid cells and intermediate cells were observed and diagnosed as intermediate grade mucoepidermoid carcinoma.

• Journal of the Korea Concrete Institute
• /
• v.12 no.3
• /
• pp.95-102
• /
• 2000

Crack control due to temperature is an important factor for the mass concrete structure. Pre-cooling is the effective system to reduce the highest temperature of mass concrete. In this study, for pre-cooling, cooling water, cooling water with ics flake are used. The results of a series of experimental studies indicate that the changes in properties of fresh concrete after cooling are of low degree, and compressive strength of concrete is changed very little by cooling. The adiabatic temperature rise is also measured with pre-cooling concrete specimens. It is shown that hydration heat characteristics of cement and concrete were largely affected by pre-cooling.

• Journal of The Korean Astronomical Society
• /
• v.48 no.1
• /
• pp.1-7
• /
• 2015

The orbital period changes of the W UMa eclipsing binary AU Ser are studied using the (O-C) method. We conclude that the period variation is due to mass transfer from the primary star to the secondary one at a very low and decreasing rate $dP/dt=-8.872{\times}10^{-8}$, superimposed on the sinusoidal variation due to a third body orbiting the binary with period $42.87{\pm}3.16$ years, orbital eccentricity $e=0.52{\pm}0.12$ and a longitude of periastron passage ${\omega}=133^{\circ}.7{\pm}15$. On studying the magnetic activity, we have concluded that the Applegate mechanism failed to describe the cycling variation of the (O-C) diagram of AU Ser.

• Journal of Advanced Marine Engineering and Technology
• /
• v.18 no.1
• /
• pp.73-80
• /
• 1994

The water ejector is a low pressure high flow rate volumetric pump. It utilize the energy of a low mass flow, high velocity stream to induce a large mass flow, low velocity stream. In addition, it has a very good resistances to cavitation compared to the other type of pumps, and the maintenance cost is practically nil. There has been enormous energy loss to supply the upper part water of dam which has large potential energy as mere irrigation water in domestic multipurpose dam. The new type of energy saving system which developed through the present study can economizes over 950,000 kWh per year by mixing the upper part water of dam with the waste water by the large water ejector. This paper estimates the economical efficiency of the new type of irrigation water pumping system, and further more, represents the change of performance characteristics of large water ejector, which was adapted to this system, according to the fluctuation of upper water level that seasonally changes.

• Bulletin of the Korean Chemical Society
• /
• v.28 no.3
• /
• pp.427-431
• /
• 2007

In order to gain insight into the molecular changes at the protein level in plants exposed to low temperature for a long period of time (vernalization), proteome analyses of vernalization-treated Arabidopsis thaliana have been carried out by two-dimensional gel electrophoresis followed by matrix-assisted laser desorption/ ionization time-of-flight mass spectrometry. Fourteen proteins including ATP binding/GTP binding/translation elongation factor and glycine-rich RNA-binding protein 7 (GRP7) showed differential expression in vernalization-treated Arabidopsis thaliana. GRP7 showed the most dramatic increase in expression suggesting its involvement in response to vernalization treatment.

• The Bulletin of The Korean Astronomical Society
• /
• v.42 no.1
• /
• pp.30.1-30.1
• /
• 2017

In the hope to detect low-surface brightness features (${\mu}_{r^{\prime}}{\sim}27\;mag\;arcsec^{-2}$), we carried out KASI-Yonsei Deep Imaging Survey for Clusters (KYDISC) targeting 14 local clusters at 0.016 < z < 0.145 using Magellan/IMACS telescope and CFHT/MegaCam. Out of 1450 cluster galaxies, 18% of galaxies show the signatures of galaxy mergers. We explore merger-driven changes from various point-of-view. We first examine color-magnitude relations, and find that galaxies related to recent mergers are populated more on blue color than their counterparts. Besides, we find the extremely low frequency of mergers on low-mass red-sequence galaxies, suggesting a migration of red galaxies into the green-valley region through merger-driven star-formation. We also study the mass-size relation of our sample, finding a larger galaxy size in galaxies related to recent mergers. Our results suggest that mergers can simultaneously change properties of galaxies, making outliers on galactic scaling relations.

• The Bulletin of The Korean Astronomical Society
• /
• v.43 no.1
• /
• pp.61.4-62
• /
• 2018

We use smoothed particle hydrodynamics (SPH) models to study the evolution of galactic spin and the distribution of gas and young stars in the inner region of the galaxies through galaxy encounters. Specifically, we perform numerical simulations of interactions of a late- or an early-type galaxy with either a late- or an early-type galaxy with and without a gas halo at the closest approach distances of 25 and 50 kpc. We find that an early-type galaxy encountering a late-type galaxy have a higher galactic spin and more gas and young stars in the central region of the galaxy after the collision. We are analyzing the role of a gas halo on the changes of galactic spin and central mass distribution during various galaxy-galaxy encounters.