• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 A
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• pp.371-373
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• 1992

This note proposes a novel robust adaptive control algorithm for systems with unknown disturbances by introducing an additional term in the control input. This additional term is easily implementable by estimating the upper bound of the unknown disturbances. By this term, the output error can be made to be uniformly ultimately bounded in a desired region via Lyapunov second stability theorem when the relative degree of system is one.

• 산업기술연구
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• 제29권B호
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• pp.41-45
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• 2009

The new cooling fan for various parts & equipments of KTX is developed and evaluated to improve fan performance and durability. The characteristic curve of the developed fan is obtained according to KSB 6311 of performance test regulation. 70 degree of the installation angle of blade makes the fan to produce a maximum flow rate. This angle is found out through trial-error and is confirmed through the verification test. In order to improve the blade strength, the blade is produced by a draw forming. The adoption of AL50 reduces a fan weight by 6 kg. The new blade makes a static pressure 170 (mmAq), a discharge rate $140(m^3/min)$, a rotational speed 2886 (rpm) at the power 10 kw. which results 54% of the static pressure improvement relative to the original blade.

• The Korean Journal of Ecology
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• 제22권6호
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• pp.363-369
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• 1999

Reconstruction of the past vegetational changes of Korea in connection with climate changes enables to understand the impacts of past and future global warming on alpine vegetation. Despite the early appearance of the cold-tolerant vegetation since the Mesozoic Era. the occurrence of warmth-tolerant vegetation during the Oligocene and Miocene implies that most of alpine and subalpine vegetations have been confined to the alpine and subalpine belts of northern Korean Peninsula. The presence of cold-episodes during the Pleistocene. however. might have caused a general southward and downslope expansions of cold-tolerant alpine and subalpine vegetation. But the climatic warming trend during the Holocene or post-glacial period eventually has isolated cold-tolerant alpine and subalpine vegetation mainly in the northern Korea. but also on scattered high mountains in the southern Korea. The presence of numerous arctic-alpine and alpine plants on the alpine and subalpine belts is mainly due to their relative degree of sensitivity to high summer temperatures. Global warming would cause important changes in species composition and altitudinal distributional pattern. The altitudinal migration of temperate vegetation upward caused by climatic warming would eventually devastate alpine plants.

• ETRI Journal
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• 제20권1호
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• pp.96-112
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• 1998

The patentability of computer program has been discussed because of its deviation from the traditional definition of a patent. The relativities of computer programs to hardware are classified to measure the relative patentability of computer programs in this paper. It can be seen through the patentability analysis that the change in patentability basically follows an exponent part of the function is a damping factor that determines a patentability degree or trend. The basic patentability of computer programs is revealed when the damping factor value is 1, and a statistical patent specification, an appropriate expression of applicability and substantiality of computer programs is needed to acquire a patent right.

• 한국농촌생활과학회지
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• 제10권1호
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• pp.33-42
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• 1999

The purpose of this study was to empirically verify the influence of variables on leisure participation and leisure satisfaction of single working people and the relative contribution of individual leisure participation and family leisure participation. The subject of this study were 176 single working people in Pusan and interviewed with a questionnaire. The data were analyzed by SPSS/PC＋ program for the frequency, mean, standard deviation, Cronbach'$\alpha$, factor analysis and regression. The major results of this study were as follows : 1. The score of family leisure participation were higher than individual leisure participation. The Level of leisure satisfaction was relatively high. 2. Variables that affect the leisure participation were job, degree of information using and perception level of the adequacy of household income. 3. Variables that affect leisure satisfaction were perception level of the adequacy of household income and individual leisure participation.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 1999년도 추계학술발표대회 논문집
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• pp.258-263
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• 1999

In this study, the numerical and experimental investigations were conducted to understand ultrasonic wave propagation and to evaluate the degree of fiber waviness in thick composites nondestructively. The path, energy and traveling time of insonified wave were predicted by adopting the ray and plane wave theories. In the analysis, the composites were assumed to have continuous fiber with sinusoidal waviness in a matrix and were modeled as stacks of infinitesimally short length off-axis elements with varying fiber orientation along the length direction. From the experiments on the specially fabricated thick composite specimens with various degrees of uniform fiber waviness, the energy distributions of received wave were obtain for the various positions of transmitter. It was observed that the energy of wave was converged to the adjacent peaks of fiber waviness. The location where maximum energy of wave was detected from the experiments showed good agreement with the location obtained from theoretical predictions. Finally, the test procedure was Proposed to evaluate fiber waviness in thick composites by considering the energy of wave and relative distance between transmitter and receiver.

• Journal of Mechanical Science and Technology
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• 제16권1호
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• pp.13-23
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• 2002

This paper presents inverse kinematic and dynamic analyses of HexaSlide type six degree-of-freedom parallel manipulators. The HexaSlide type parallel manipulators (HSM) can be characterized as an architecture with constant link lengths that are attached to moving sliders on the ground and to a mobile platform. In the inverse kinematic analyses, the slider and link motion (position, velocity, and acceleration) is computed given the desired mobile platform motion. Based on the inverse kinematic analysis, in order to compute the required actuator forces given the desired platform motion, inverse dynamic equations of motion of a parallel manipulator is derived by the Newton-Euler approach. In this derivation, the joint friction as well as all link inertia are included. Relative importance of the link inertia and joint frictions on the computed torque is investigated by computer simulations. It is expected that the inverse kinematic and dynamic equations can be used in the computed torque control and model-based adaptive control strategies.

• 대한전자공학회논문지
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• 제26권8호
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• pp.1167-1177
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• 1989

In this paper, a generalized adaptive law is proposed which uses a rational function type operator for parameter adjustment. To satisfy the passivity condition of the adaptation block, we introduce a constant feedback gain into the adaptation block. This adaptation scheme is applied to the model reference adaptive control of a continuous-time, linear time-invariant, minimum-phase system whose relative degree is 1. We prove the asymptotic stability of the output error of this adaptive system by hyperstability method. It is shown that by digital computer simulations this law can give a better output error transient response in some cases than the conventional gradient adaptive law. And the output error responses for the several types of the proposed adaptation law are examined in the presence of a kind of unmodeled dynamics.

• 반도체디스플레이기술학회지
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• 제2권2호
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• pp.1-4
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• 2003

We have developed a rotating compensator spectroscopic ellipsometer (RCSE). As the ellipsometry measures a change in the polarization state of a light wave upon non-normal reflection from surface, the degree of sensitivity is enhanced greatly through the detection of relative phase change. RCSE acquires additional information from the non-ideal surface of sample and operates over the photon energy range from 1.5 to 4.5 eV. We applied RCSE to measure the optical properties of films and the line-width of patterned PR films on crystalline silicon.

• 품질경영학회지
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• 제40권3호
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• pp.381-393
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• 2012

Purpose: Considering various measurements for healthcare service quality, the purpose of this study is to examine measurement items for healthcare service quality (HCSQ) based on previous study and service quality evaluation institutions in the international community. Methods: The proposed research model was tested using measurement analysis, based on data collected from 387 respondents in the selected hospital with more than 500 beds in South Korea. Results: The results of the study shed insights about the relative importance of quality items as degree of improvements of care services tangible, safety, efficiency, and empathy. Also, the study provides new measurement model for healthcare service quality. Conclusion: Healthcare organization thrives to find the key factors for improving quality of care and service that meet customers' needs and expectations.