• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.1209-1212
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• 1996

In this paper, we design a stabilizing controller with disturbance rejection properties for multirate sampled-data systems which have periodic output measurement scheme. We assume that the plant is open-loop unstable and the disturbance consists of a sum of finite number of sine waves with different frequencies. A sufficient condition for maintaining observability in multirate sampled-data systems is derived. The proposed controller has an IMC structure and can be decomposed into the filtered-disturbance estimator and the inverse of the fast uniform sampled model of the pre-stabilized plant. An example is presented for illustrations.

• International Journal of Internet, Broadcasting and Communication
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• 제4권2호
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• pp.22-27
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• 2012

The design characteristics of circular vertical-cavity surface-emitting lasers are studied by using a newly developed equivalent network. Optical parameters, such as the stop-band or the reflectivity of periodic mirrors and the resonance wavelength, are explored for the design of these structures. To evaluate the differential quantum efficiency and the threshold current density, a transverse resonance condition of modal transmission-line theory is also utilized. This approach dramatically reduces the computational time as well as gives an explicit insight to explore the optical characteristics of circular vertical-cavity surface-emitting lasers (VCSELs).

• 대한전기학회:학술대회논문집
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• 대한전기학회 1989년도 추계학술대회 논문집 학회본부
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• pp.53-57
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• 1989

Until now, method of equivalent circuit is generally used in analyzing the characteristic of the synchronous alternator. But this method can't apply when loads are connected to alternator. In this paper, we analyzed the load characteristic of the synchronous alternator with permanant magnet using 2-dimensional finite element method having voltage source. The loads of a alternator are battary and diodes which are used to rectify. also, we used half periodic boundary condition in the F.E.M calculation

• 대한수학회지
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• 제57권1호
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• pp.61-88
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• 2020

In this paper, we investigate the existence of mild solutions for a class of fractional impulsive evolution equation with periodic boundary condition by means of the method of upper and lower solutions and monotone iterative method. Using the theory of Kuratowski measure of noncompactness, a series of results about mild solutions are obtained. Finally, two examples are given to illustrate our results.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2005년도 연구개발 발표회 논문집
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• pp.437-440
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• 2005

In the present work, characteristics of the flow in CAGE of a steam turbine LP/HP Bypass control valve for thermal power plant are investigated. The flow field is analyzed numerically by solving steady three-dimensional Reynolds-averaged Navier-Stokes equations. Shear stress transport (SST) model is used as turbulence closure.

• Journal of applied mathematics & informatics
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• 제23권1_2호
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• pp.571-579
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• 2007

Finite difference schemes are considered for a generalization of the Cahn-Hilliard equation with Neumann boundary conditions and the Kuramoto-Sivashinsky equation with a periodic boundary condition, which is of the type $ut+\frac{{\partial}^2} {{\partial}x^2}\;g\;(u,\;u_x,\;u_{xx})=f(u,\;u_x,\;u_{xx})$. Stability and $L^{\infty}$ error estimates of approximate solutions for the corresponding schemes are obtained using the extended Lax-Richtmyer equivalence theorem.

• Journal of applied mathematics & informatics
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• 제28권5_6호
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• pp.1089-1099
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• 2010

An SIR epidemic model with pulse vaccination and time delay describing infection period is investigated. The global attractiveness of the infection-free periodic solution is discussed, and sufficient condition is obtained for the permanence of the system. Our results indicate that a large vaccination rate or a short period of pulsing leads to the eradication of the disease.

• Bulletin of the Korean Chemical Society
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• 제13권6호
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• pp.665-669
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• 1992

We consider the problem of a random walker on a one-dimensional lattice (N sites) confronting a centrally-located deep trap (trapping probability, T=1) and N-1 adjacent sites at each of which there is a nonzero probability s(0 < s < 1) of the walker being trapped. Exact analytic expressions for < n > and the average number of steps required for trapping for arbitrary s are obtained for two types of finite boundary conditions (confining and reflecting) and for the infinite periodic chain. For the latter case of boundary condition, Montroll's exact result is recovered when s is set to zero.

• 치위생과학회지
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• 제7권2호
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• pp.73-79
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• 2007

본 연구는 지속적인 건강증진을 위해 운동을 하는 대상자들의 건강관리 행위와 구강보건지식과의 관계를 알아보기 위해 경기지역에 거주하는 성인을 대상으로 230부의 설문조사 하였으며, SPSSWIN 12.0을 이용하여 분석한 결과 다음과 같은 결론을 얻었다. 1. 대상자들의 정기적인 건강검진경험 유무는 받는다 38.2%, 안받는다 61.8% 이었고, 정기적인 구강검진경험 유무는 받는다 30.7%, 안받는다 69.3%로 나타났다. 2. 대상자들의 구강보건교육경험의 유무는 받은 경험이 있다 11.8%, 받은 경험이 없다88.2%로 나타났다. 3. 대상자들 중 정기검진을 받는 응답자의 일반적 특성과 건강관리실태와의 관계에 있어서는 연령, 직업, 운동을 하는 이유의 항목에서 통계적으로 유의한 차이를 나타냈다(p < 0.05). 4. 성별에 따른 구강보건지식과의 관계에 있어서는 전체적으로 이를 닦는 시간은 3분정도가 적당하다에서 68.4%의 높은 결과를 나타냈으나 통계적으로 유의한 차이를 보이지는 않았다. 5. 연령에 따른 구강보건지식과의 관계에 있어서는 이를 닦는 시기는 매 식사 후와 잠자기 전이다(p = .032), 불소를 이용하면 치아우식을 예방할 수 있다(p = .011), 충치를 유발하는 식품에는 초콜릿, 비스킷 등이 있다(p = .044)에서 통계적으로 유의한 차이를 나타냈다(p < 0.05). 6. 직업에 따른 구강보건지식과의 관계에 있어서는 전체적으로 이를 닦는 시간은 3분정도가 적당하다(p = .043)에서 68.4%로 가장 높게 나타나고, 통계적으로 유의한 차이를 보였다(p < 0.05). 7. 정기적인 검진을 하고 있는 대상자와 구강보건지식과의 관계에 있어서는 통계적으로 유의한 차이를 보이지 않았다.

• 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).