• 로봇학회논문지
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• 제2권1호
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• pp.64-70
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• 2007

In this paper, a robotic system which consists of a precision manipulator and a micro gripper for a micro system assembly is presented. By the experiment, we proved that the developed the system gives acceptable performance when minute operations. Developed the micro-nano robot is actuated by newly proposed modular revolute and prismatic actuators. As an end-effector of this system, micro gripper is designed and fabricated with MEMS technology and the displacement of jaw is up to 142.8 micro meter. We think that new robot system will be appropriate for micro system assembly tasks and life science application.

• 제어로봇시스템학회논문지
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• 제14권8호
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• pp.842-847
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• 2008

This paper proposes a new sliding-surface-based tracking control system for nonholonomic mobile robots with disturbance. To design a robust controller, we consider the kinematic model and the dynamic model of mobile robots with disturbance. We also propose a new sliding surface to solve the problem of previous study. That is, since the new sliding surface is composed of differentiable functions unlike the previous study, we can obtain the control law for arbitrary trajectories without any constraints. From the Lyapunov stability theory, we prove that the position tracking errors and the heading direction error converge to zero. Finally, we perform the computer simulations to demonstrate the performance of the proposed control system.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집
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• pp.486-489
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• 2002

Temperature(T) dependence of the sheet resistance( $R_{$\square$}$) has been investigated on the c-axis oriented thin films of the (Bi2212/Bi2201) mixed crystal with different molar fractions. The $R_{$\square$}$-T superconducting characteristic deteriorated with reduction of the Bi2212 fraction, and almost disappears at 48 mol% where a superconductor-to-insulator transition took place, with the resistance on the normal state, RN, reaching 4.l㏀ at 80 K. This $R_{N}$ value is close to the universal quantum number, h/(2e)$^2$≡6.5㏀ predicted by the Kosterlitz-Thouless(KT) transition theory. The $R_{$\square$}$-T characteristics of the 48 mol% thin film can be elucidated as a competitive process of KT transition brought about by charge or vortex in the two-dimensional layer structure.e.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 추계학술대회 논문집 Vol.18
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• pp.329-330
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• 2005

Bi-Sr-Ca-Cu-O thin films have been fabricated by sputter deposition method. During the deposition, 10 and 90 wt%-ozone/oxygen mixture gas of typical pressure of $1\sim9\times10^{-5}$ Torr are supplied with ultraviolet light irradiation for oxidation. XRD and RHEED investigations reveal out that a buffer layer with some different compositions is formed at the early deposition stage of less than 10 units cell and then Bi-2201 oriented along the c-axis is grown.

• 한국수산과학회지
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• 제29권6호
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• pp.917-919
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• 1996

• 한국정밀공학회지
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• 제16권10호
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• pp.101-108
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• 1999

Most of researches for deep drawing process have been performed on the formability of axisymmetric blank, but there is an insufficient study on the formability of non-axisymmetric blank. In addition, the conventional blank shape has been determined by the trial-and-error method using industrial experience and post processing test. Therefore only approximated shape of the blank can be presented. In this study, the optimal blank shape and concrete drafting method in deep drawing process with biaxisymmetric elliptical shape is proposed. Through the deep drawing experiment, it is found that the optimal blank shape gives the most uniform thickness of the products in the first process

• 한국수정란이식학회:학술대회논문집
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• 한국수정란이식학회 2006년도 The 6th Intermational Symposium on Developmental Biotechnology
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• pp.108-108
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• 2006

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.1465-1468
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• 2006

Railway is superior to the other land transportation systems in aspects of environmental problems. Environmental problems are not considered during a preliminary feasibility study. Investment for railway is low because of low B/C(benefit/cost)ratio in the economical efficiency analysis during the preliminary feasibility study. The body of this paper studies the railway noise which can reflect environmental problems an assessment of environmental impact. The body of this paper studies the presumption of The Benefit Cost of railroad noise arresting it will be able to reflect the evaluation environmental matter of the effect which it gives to an environment.

• 천문학회보
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• 제36권2호
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• pp.84.1-84.1
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• 2011

In this study, we intend to inquire of how the temporal variation and spatial distribution of magnetic helicity injection in a CME-producing solar active region are related to the CME occurrence. We therefore investigate long-term (a few days) variation of magnetic helicity injection in the active region NOAA 9236 which produced multiple CME events. As a result, it is found that a noticeable increase in helicity of negative sign was first made for the first ~1.5 days and then 6 CMEs occurred while the relatively more injection of oppositely signed (positive) helicity was taking place for the next ~2 days. Afterwards, 2 CMEs in the region occurred while a more negative helicity is being injected again compared to a positive helicity. In addition, from helicity flux density maps, we found that the CMEs originated from this active region seem to be involved with the interaction of two magnetic field systems characterized by opposite signs of helicity.

• 전기학회논문지P
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• 제51권4호
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• pp.198-205
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• 2002

In this paper, we proposed a wavelet image coder based on the portable embedded microprocessor. The proposed coder stores the bit level information of the wavelet coefficient in the 2D significance array. Using this information, the coder make the significance check for coefficient and bit level scanning at the same pass. The proposed method has the advantage that we can reduce the scan iteratively and the memory usage for the coding process. Experimental results show that the proposed method outperforms popular image coders such as JPEG, EZW and SPIHT in based on the portable embedded system environment.