• 제목/요약/키워드: 1st-order system

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적응 뉴로 퍼지추론 기법에 의한 비선형 시스템의 구조 동정에 관한 연구 (Structure Identification of Nonlinear System Using Adaptive Neuro-Fuzzy Inference Technique)

  • 이준탁;정형환;심영진;김형배;박영식
    • 한국지능시스템학회:학술대회논문집
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    • 한국퍼지및지능시스템학회 1996년도 추계학술대회 학술발표 논문집
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    • pp.298-301
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    • 1996
  • This paper describes the structure Identification of nonlinear function using Adaptive Neuro-Fuzzy Inference Technique(ANFIS). Nonlinear mapping relationship between inputs and outputs were modeled by Sugeno-Takaki's Fuzzy Inference Method. Specially, the consequent parts were identified using a series of 1st order equations and the antecedent parts using triangular type membership function or bell type ones. According to learning Rules of ANFIS, adjustable parameters were converged rapidly and accurately.

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언커플시스템의 파라메트릭 모델링 (Parametric Modelling of Uncoupled System)

  • 윤문철;김종도;김광희
    • 한국기계가공학회지
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    • 제5권3호
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    • pp.36-42
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    • 2006
  • The analytical realization of uncoupled system was introduced in this study using times series and its spectrum analysis. The ARMAX spectra of time series methods were compared with the conventional FFT spectrum. Also, the response of second order system uncoupled was solved using the Runge-Kutta Gill method. In this numerical analysis, the displacement, velocity and acceleration were calculated. The displacement response among them was used for the power spectrum analysis. The ARMAX algorithm in time series was proved to be appropriate for the mode estimation and spectrum analysis. Using the separate response of first and second mode, each modes were calculated separately and the response of mixed modes was also analyzed for the mode estimation using several time series methods.

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일부농촌지역의 상병상태연구(충남 서산군) (A Study on the morbidity of rural populations (Seosan County Choong Nam province))

  • 안문영
    • Journal of Preventive Medicine and Public Health
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    • 제17권1호
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    • pp.107-119
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    • 1984
  • At the preliminary survey of Seosan demonstration project for integration of family planning and maternal and child health service, 6 questions about morbid conditions of all household members were included. Definition of morbid condition used at the survey was self-conceived physical or mental infirmity which had been caused by diseases or accidents, resulting in obstacles to ordinary daily life for past 30 days. Analyzing those morbidity data, the following results were obtained. 1. The morbid person rate was 192.2 per 1,000 persons and the morbidity rate 214.2 per 1,000 persons. 2. The percentage of household which had at least one morbid person was 61.9% and average number of morbidity per one household was 1.1. 3. Analyzing the 1st morbid condition of the total 4,433 morbid persons, morbidity rate of male was 194.6 per 1,000 persons and that of female was 189.8 per 1,000 persons. 4. The highest age specific morbidity rate was that of $0{\sim}4$ years of age, and it was 304.3 per 1,000 persons. The lowest was that of $10{\sim}14$ years of age and the rate of 93.8 per 1,000 persons. 5. The following was the order of five major diseases which were classified according to 17 International Classification of Diseases. (1) Symptoms and Ill defined conditions : 17.3% (2) Disease of the Digestive system : 15.7% (3) Infections and Parasitic disease 14.3% (4) Disease of the Respiratory system : 13.7% (5) Disease of the Nervous system and sense organs : 9.4% 6. 30 leading morbid conditions were described in Table III-2 and which composed 70.6% of total morbid conditions. 7. The percentage of the morbid conditions of which duration was longer than 90 days was 40.5%. 8. Of the total 4,433 morbid persons, 4,394 morbid persons responded for the morbid condition management method. Of those, Hospital & clinic (35.3%), drug store (40.0%), herb drug store (3.6%), health center (2.2%) ware selected for the 1st place or method for management morbid condition, and 18.0% did not search for morbid condition management.

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커플시스템의 모우드 분석 연구 (Mode Analysis of Coupled System)

  • 김종도;윤문철
    • 한국기계가공학회지
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    • 제9권3호
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    • pp.28-34
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    • 2010
  • The suggested coupled system was analyzed using FRF and mode analysis. The eigen-mode of FRF analysis is consistent with that of conventional FFT in spectrum. Also, three numerical responses of second order system, which are coupled, was obtained using the Runge-Kutta Gill method. The displacement, velocity and acceleration response were calculated for the numerical analysis of coupled system and the displacement response was used for the calculation of FRF of this system. Using the mixed response of 1st and 2nd mode in example, the FRF was analysed for the analysis of mixed mode coupled system. Also, its mode shape was acquired by solving the eigen problem of coupled system.

밀리타리스 동충하초(Cordyceps militaris)의 면역 활성에 미치는 영향 (Effects of Cordyceps militaris on Immune Activity)

  • 강인순;김혜주;이태호;권용삼;손미원;김채균
    • 약학회지
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    • 제58권2호
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    • pp.81-90
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    • 2014
  • In order to determine the functional benefits of Cordyceps militaris in the immune system, we examined the immunomodulatory activities of C. militaris using an immunocompromised C57BL/6 mice, mouse spleen cells, RAW 264.7 macrophage cells, and A549 lung carcinoma cells. Mice were injected intraperitioneally with an immunosuppressive drug, cyclophosphamide, and then administered orally with 30, 100 and 300 mg/kg of 50% ethanol extract of C. militaris (CME 30, CME 100 and CME 300) for 14 days. CME increased splenocyte proliferation and natural killer (NK) cell activity compared to 3% hydroxypropyl methylcellulose-treated control mice. CME also increased the production of Th1 cytokines, IL-2 and TNF-${\alpha}$ in spleen cells isolated from CME-injected mice and in vitro, which suggested the enhanced cellular immunity in response to CME. CME also increased splenocyte proliferation, NK cell activity, and IL-2 and TNF-${\alpha}$ production compared to 1 ${\mu}M$ methotrexate-treated spleen cells in vitro. We examined whether C. militaris regulates the production of inflammatory mediators in LPS-stimulated RAW 264.7 cells. CME inhibited LPS-induced NO production and iNOS expression in a dose dependent manner, while COX-2 expression was remained unchanged. In addition, CME also has free radical scavenging activity, indicating its antioxidant activity. These results indicate that C. militaris enhances immune activity by promoting immune cell proliferation and cytokine production.

크리깅 모델을 이용한 곱분해 기법에서 정확하고 강건한 통계적 모멘트 계산을 위한 전역모델의 비교 분석 (Comparison of global models for calculation of accurate and robust statistical moments in MD method based Kriging metamodel)

  • 김태균;이태희
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2008년도 추계학술대회A
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    • pp.678-683
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    • 2008
  • Moment-based reliability analysis is the method to calculate reliability using Pearson System with first-four raw moments obtained from simulation model. But it is too expensive to calculate first four moments from complicate simulation model. To overcome this drawback the MD(multiplicative decomposition) method which approximates simulation model to kriging metamodel and calculates first four raw moments explicitly with multiplicative decomposition techniques. In general, kriging metamodel is an interpolation model that is decomposed of global model and local model. The global model, in general, can be used as the constant global model, the 1st order global model, or the 2nd order global model. In this paper, the influences of global models on the accuracy and robustness of raw moments are examined and compared. Finally, we suggest the best global model which can provide exact and robust raw moments using MD method.

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Analysis of an AC/DC Resonant Pulse Power Converter for Energy Harvesting Using a Micro Piezoelectric Device

  • Chung Gyo-Bum;Ngo Khai D.T.
    • Journal of Power Electronics
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    • 제5권4호
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    • pp.247-256
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    • 2005
  • In order to harvest power in an efficient manner from a micro piezoelectric (PZT) device for charging the battery of a remote system, a new AC/DC resonant pulse power converter is proposed. The proposed power converter has two stages in the power conversion process. The first stage includes N-type MOSFET full bridge rectifier. The second stage includes a boost converter having an N-type MOSFET and a P-type MOSFET. MOSFETs work in the $1^{st}$ or $3^{rd}$ quadrant region. A small inductor for the boost converter is assigned in order to make the size of the power converter as small as possible, which makes the on-interval of the MOSFET switch of the boost converter ultimately short. Due to this short on-interval, the parasitic junction capacitances of MOSFETs affect the performance of the power converter system. In this paper, the performance of the new converter is analytically and experimentally evaluated with consideration of the parasitic capacitance of switching devices.

점성댐퍼를 갖는 엔진 축계의 비선형 비틀림강제진동 (Nonlinear Forced Torsional Vibration for the Engine Shafting System With Viscous Damper)

  • 박용남;송성옥;김의간;전효중
    • Journal of Advanced Marine Engineering and Technology
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    • 제20권4호
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    • pp.50-58
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    • 1996
  • The torsional vibration of the propulsion shafting system equipped with viscous damper is investigated. The equivalent system is modeled by a two mass softening system with Duffing's oscillator and the vibratory motion is described by non-linear differential equations of second order. The damper casing is fixed at the front-end of crankshaft and the damper's inertia ring floats in viscous silicon fluid inside of the camper casing. The excitation frenquency is proportional to the rotational speed of engine. The steady state response of the equivalent system is analyzed by the computer and for this analyzing, the harmonic balance method is adopted as a non-linear vibration analysis technique. Frequency response curves are obtained for 1st order resonance only. Jump phenomena are explained. The discriminant for the solutions of the steady state response is derived. Both theoretical and measured results of the propulsion shafting system are compared with and evaluated. As a result of comparisions with both data, it was confirmed that Duffing's oscillator can be used in the modeling of the propulsion shafting system attached with viscous damper with non-linear stiffness.

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점성댐퍼를 갖는 엔진 축계의 비선형 비틀림강제진동 (Nonlinear Forced Torsional Vibration for the Engine Shafting System With Viscous Damper)

  • 박용남;송성옥;김의간;전효중
    • Journal of Advanced Marine Engineering and Technology
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    • 제20권4호
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    • pp.372-372
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    • 1996
  • The torsional vibration of the propulsion shafting system equipped with viscous damper is investigated. The equivalent system is modeled by a two mass softening system with Duffing's oscillator and the vibratory motion is described by non-linear differential equations of second order. The damper casing is fixed at the front-end of crankshaft and the damper's inertia ring floats in viscous silicon fluid inside of the camper casing. The excitation frenquency is proportional to the rotational speed of engine. The steady state response of the equivalent system is analyzed by the computer and for this analyzing, the harmonic balance method is adopted as a non-linear vibration analysis technique. Frequency response curves are obtained for 1st order resonance only. Jump phenomena are explained. The discriminant for the solutions of the steady state response is derived. Both theoretical and measured results of the propulsion shafting system are compared with and evaluated. As a result of comparisions with both data, it was confirmed that Duffing's oscillator can be used in the modeling of the propulsion shafting system attached with viscous damper with non-linear stiffness.

공동주택 이중바닥구조의 바닥충격음 저감성능 (Floor Impact Noise Reduction Performance of Double-Floor System in Apartments)

  • 백길옥;박홍근;문대호
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2014년도 추계학술대회 논문집
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    • pp.197-202
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    • 2014
  • Floor Impact Noise is a structure-borne noise which is mainly caused by vibration of concrete slabs. The majority of previous studies have focused on investigating performance of absorbing sheets on the reduction of floor impact noise. But absorbing sheets do not efficiently reduce heavy-weight floor impact noise level because it cannot absorb slab vibration, which is the fundamental noise source. In this study, double-floor system was developed in order to reduce floor impact noise level in residual buildings. This floor system reduces heavy-weight impact noise level by reducing vibration response at the center of slab, which has maximum amplitude in the 1st vibration mode. In order to identify the performance of the double-floor system, experiments were planned. Primary test parameters are span of double floor, arrangement and types of absorbing sheets.

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