• 지역사회간호학회지
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• 제4권1호
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• pp.14-24
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• 1993

The Purpose of this study was to explore the condition of periodic medical examination and the health care services of industries in order to offer some basic data on developing industrial nursing care. To achieve this goal a self - administered questionnaire (developed by the academic affairs of community health nursing) was provieded to the nurses in 56 industries from Dec. 10, 1992 to Jan. 20, 1993. The statistical computer package, SPSS, was used to manipulate the data along with T-test and ANOVA. The results were as follows : 1. General characteristics: The greater part of the industries were manufacturing company, and below 300 employees of industry were 55.4%. The shift system was mostly one shift(66.1%) and three shift(23.2%), and 50.0% them organized the Industrial Safety and Health Commitee. Average a number of employees was 631 person. 2. Periodic Medical Examination: Most of the workers were receiving periodic medical examination from the designated hospital (95.71%). From the about 12.89% were gone through a colse medical examination. In colse medical examination 58.41% were decided 'C' and 36.73% were decided 'D'. About 6.23% off those who had any clinical findings were work-time shortening(7.84%), work-transition(8.12%), recoverating at home. The majority of the workers receive the result of the periodic medical examination individually (78.5%). 3. Special medical examination: The rate of those who are receiving special medical examination were 76.82% and about 8.24% were decided 'C' and 1.23% were decided 'D' Those who had any health problems were receiving follow-up checking (9.10%) and medical treatment while working (15.04%). The health managers in the company can consult (85.7%) those who had any suspicious sign and symptoms of occupational disease. 4. Health care services: The average score of health care services were 17.57 point out of 28 point, and the score was lower in health assessment and environmental hygiene than medical diagnosis and health education. There were significant differences in environmental hygine (F=3.72, P=0.017), health care services(F=3.94, P=0.013) according to the size of the size of the industries The other's significancy is not shown by any type of industrial nurse. The level of health care services were higher in the wokers who had better health and showed no singificant differences(T=-0.73, P=0.470).

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2011년도 춘계학술대회 논문집
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• pp.250-257
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• 2011

The power input to an infinite cylindrical shell excited by a point force is investigated. The circumferential direction and axial direction of the cylindrical shell is assumed as a two-dimensional unbounded medium, and the point force is replaced as a periodic array of imaginary sources. The spatial Fourier transform is taken from the equation of motion of the cylindrical shell, which is derived from the static model of Donell-Mushtari-Vlasov. The inverse Fourier transform is taken to derive the vibration responses. Mobility from out-of-plane forces and in-plane forces are derived from the obtained vibration responses. The theory is applied to a cylindrical shell excited by a normal direction of point force.

• Journal of Electrical Engineering and Technology
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• 제13권4호
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• pp.1644-1654
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• 2018

Eigenvalue distributions for a periodic metal-insulator-metal waveguide, classified into the point spectrum and the discretized continuous spectrum (DCS), are investigated as functions of frequencies, gap widths, and periods. Muller's method is suggested for solving exact eigenvalues, and we propose the scheme for finding proper initial values in the Muller's method by considering only ${\Re}e({\varepsilon}_r)$ in the dispersion equation. We then find that anti-crossing behavior, repulsive effect between the point spectrum and the DCS, becomes stronger when the real parts of the roots in the point spectrum have smaller values. Finally, we examine the transmittances of a single subwavelength slit for real metals using the mode matching technique. The transmittances in real metals similarly follow those of the perfect electric conductor (PEC) at low frequencies, while the patterns at higher frequencies begin to differ from the PEC.

• 한국정밀공학회지
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• 제14권4호
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• pp.119-125
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• 1997

The drilling experiment of carbon fiber epoxy composite material with WC-drill has been done under the various cutting conditions in order to minimize the problems occurred in the material while being drilled. It has been confirmed by a frequency analysis of the cutting force signals that the variation of cutting force resulted from the periodic variation of the angle between the ortating drill and the stacking angle of the carbon fiber. By the drilling experiment with several drills having different point angles, the drilling char- acteristics, which show the relations between the change in the point angle and cutting force or external surface condition, were analyzed.

• 제어로봇시스템학회논문지
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• 제9권2호
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• pp.117-123
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• 2003

Rotational machines such as optical disk drives, hard disk drives, and so on are subject to periodic disturbances caused by their mechanical characteristics. In the meanwhile, it is well known that repetitive control rejects periodic disturbance effectively. This paper presents a practical application of repetitive control to the track-following servo of an optical disk drive. The repetitive control system is composed of two repetitive controllers which compensate for periodic disturbances generated by track geometry and eccentric rotation of disk and a feedback controller stabilizing the feedback loop. A robust stability for all plant uncertainties is proved using linear matrix inequalities (LMIs). In the controller design, a weighting function is introduced for the feedback controller to ensure a minimum loop gain and a sufficient phase margin. The repetitive controllers and the feedback controller are designed by solving an optimization problem which can consider the robust stability condition and the system performance. The developed repetitive control system is implemented in the digital control system with a 16-bit fixed-point digital signal processor (DSP). Through simulation and experiment. The feasibility of the proposed repetitive control system is verified.

• 대한수학회지
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• 제37권5호
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• pp.665-685
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• 2000

The aim of this paper is to obtain nonlinear operators in suitable spaces whise fixed point coincide with the solutions of the nonlinear boundary value problems ($\Phi$($\upsilon$'))'=f(t, u, u'), l(u, u') = 0, where l(u, u')=0 denotes the Dirichlet, Neumann or periodic boundary conditions on [0, T], $\Phi$: N N is a suitable monotone monotone homemorphism and f:[0, T] N N is a Caratheodory function. The special case where $\Phi$(u) is the vector p-Laplacian $\mid$u$\mid$p-2u with p>1, is considered, and the applications deal with asymptotically positive homeogeneous nonlinearities and the Dirichlet problem for generalized Lienard systems.

• 한국소음진동공학회논문집
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• 제13권4호
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• pp.317-322
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• 2003

Torsional oscillations of a system incorporating a Hooke's joint are investigated by adopting a nonlinear 2-degree-of-freedom model. Linear and Van der Pol transformations are applied to obtain the equations of motion to which the method of averaging can be readily applied. Various subharmonic and combination resonances are identified with the conditions of their occurrences. Applying the method of averaging leads to the reduced amplitude- and phase-equations of motion, of which constant and periodic solutions are obtained numerically. The periodic solution which emerges from Hopf bifurcation point experiences period doubling bifurcation leading to infinite solution rather than chaotic solution.

• Journal of information and communication convergence engineering
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• 제9권3호
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• pp.295-300
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• 2011

Twitter is a popular microblogging service that enables the users to send and read short text messages. These messages are becoming source to analyze topic trends and identify relations among temporal topics. In this paper, we propose a method to classify the temporal topics on Twitter as a problem of grouping the similar patterns. To provide a starting point for a classification under the same topics, we identify the content word weighting scheme based on Latent Dirichlet Allocation (LDA). And we formulate how the temporal topics in the time window can be classified like peaky topics, constant topics, and periodic topics. We provide different real case studies which show the validity of the proposed method. Evaluations show that the proposed method is useful as a classifying model in the analysis of the temporal topics.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1998년도 춘계학술대회논문집; 용평리조트 타워콘도, 21-22 May 1998
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• pp.88-93
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• 1998

Since rattling noise, which occur in mechanical linkage with free play or glove boxes in passenger cars, play an important role in the generation of industrial noise and vibration, it is interest to study these dynamics. A difference equations are derived which described the motions of a mass constrained by pre-compressed spring and forced by a high frequency base excitation. Two types of saddle are founded from these difference equations and the stable and unstable manifolds are constructed in these saddle point. For a certain region in a parameter space of exciting displacement and coefficient of restitution, transversal intersections of stable and unstable manifolds exist. Therefore it is founded that there are large families of periodic and irregular non-periodic motions in rattling system i.e. chaos motion is observed.

• 한국광학회:학술대회논문집
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• 한국광학회 2000년도 제11회 정기총회 및 00년 동계학술발표회 논문집
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• pp.1-1
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• 2000

The interaction of light with periodic patterns generates beautiful color patterns and interesting applications. The basic equation for understanding this phenomena is the grating equation. It tells us the angles, relative to a perpendicular to a grating with a specific period, into which light of a specific wavelength will be diffracted. But what it does not tell us is how much light will be directed into the various "orders" of the grating. It was found that by controlling the shape of the diamond point used to cut the periodic structure into the substrate, a traditional grating could be made to direct most of the light diffracted from it into a single order. This type of grating is referred to as a "blazed" grating. (omitted); grating. (omitted)