• 제목/요약/키워드: Prediction equation

검색결과 1,882건 처리시간 0.028초

Development of Bioelectrical Impedance Analyzer for Korean in Telemedicine (원격의료계측을 위한 한국형 생체 전기 임피던스 분석 시스템의 개발)

  • 문재국;서광석;임택균;신태민;윤형로
    • Journal of Biomedical Engineering Research
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    • 제23권5호
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    • pp.413-418
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    • 2002
  • The purpose of this study was to design a single frequency BIA(Bioelectrical Impedance Analyzer) which can measure body impedance when patient is sitting on the toilet and to develope a prediction equation for designed BIA. For the purpose of this study, we acquired body impedances with designed BIA from 181 subjects composed of healthy Korean by attaching electrodes to suitable positions(wrist and thigh) for toilet measurement. We computed an appropriate FFM(Fat Free Mass) for Korean using modified-Siri equation to the same subjects instead of Siri equation which nay cause accuracy problems in hydrodensitometry when it applied to Korean. We used this FFM as reference value and developed a Korean FFM prediction equation based on body impedance index, body weight and sex. Correlation coefficient between prediction value and reference value of FFM was extremely high (r = 0.977) and SEE(Standard Error of Estimation) was low 2.47kg.(p<0.05) For comparison between existing electrode-attaching method and our method for toilet measurement, we acquired body impedance with designed BIA from same subjects attaching electrodes on existing positions (wrist and ankle) and made FFM prediction equation for BIA. Correlation coeffient between predicted value and reference value was 0.978 and SEE was 2.43kg(p<0.05). It means that the developed system has not significant differences with existing method. In conclusion bioelectrical impedance analyzer and the FFM prediction equation developed in this paper are evaluated to he adequate to compute FFM of Korean.

Development of a Tool Life Prediction Program for Increasing Reliability of Cutting Tools (공구의 신뢰성 향상을 위한 수명 예측 프로그램 개발)

  • Kim Bong-Suk;Kang Tae-Han;Kang Jae-Hun;Song Jun-Yeob;Lee Soo-Hun
    • Transactions of the Korean Society of Machine Tool Engineers
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    • 제14권3호
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    • pp.1-7
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    • 2005
  • The prediction for tool life is one of the most important factors for increasing reliability, stability, and productivity of manufacturing system. This paper deals with a tool life prediction method in view of reliability assessment for cutting tools. In this study, flank wear was focused among multi-factors deciding the tool wear state. First, tool life was predicted by correlation between flank wear and cutting time, based on the extended Taylor tool life equation of turning, including parameters of cutting speed, feed rate, and cutting depth. Second, each of cutting conditions of end-milling was equivalently converted to apply ball end-mill data to the extended Taylor equation. The web-based prediction program for tool life was developed as one of reliability assessment programs for machine tools.

RBF Network Structure for Prediction of Non-linear, Non-stationary Time Series (비선형, 비정상 시계열 예측을 위한 RBF(Radial Basis Function) 회로망 구조)

  • Kim, Sang-Hwan;Lee, Jong-Ho
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • 제48권2호
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    • pp.168-175
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    • 1999
  • In this paper, a modified RBF(Radial Basis Function) network structure is suggested for the prediction of a time-series with non-linear, non-stationary characteristics. Coventional RBF network predicting time series by using past outputs sense the trajectory of the time series and react when there exists strong relation between input and hidden activation function's RBF center. But this response is highly sensitive to level and trend of time serieses. In order to overcome such dependencies, hidden activation functions are modified to react to the increments of input variable and multiplied by increment(or dectement) for prediction. When the suggested structure is applied to prediction of Macyey-Glass chaotic time series, Lorenz equation, and Rossler equation, improved performances are obtained.

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Friction Welding of Dissimilar Hot Die Punch materials and Its Creep Life Prediction(II)-Creep Life Prediction by ISM (열간 금형재의 이종재 마찰용접과 크리프 수명예측 (II) -크리프 수명예측)

  • 박일동;공유식;오세규;전태언
    • Journal of Ocean Engineering and Technology
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    • 제15권2호
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    • pp.53-60
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    • 2001
  • It was confirmed that the life predictive equation by LMP and LMP-ISM are effective only up to 10$^2$hours and can not be used for long times of $10^3~10^5$ hours, but that by ISM can be used for long times creep life prediction with more reliability. The predictive creep life equation of ISM has better reliability than those by LMP and LMP-ISM, and its realizably is getting better for long time creep prediction($10^3~10^5$ h).

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Prediction of Concrete Strength Using Artificial Neural Networks (인공신경망을 이용한 콘크리트 강도 추정)

  • 이승창;안정찬;정문영;임재홍
    • Proceedings of the Korea Concrete Institute Conference
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    • 한국콘크리트학회 2002년도 봄 학술발표회 논문집
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    • pp.997-1002
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    • 2002
  • Traditional prediction models have been developed with a fixed equation form based on the limited number of data and parameters. If new data is quite different from original data, then the model should update not only its coefficients but also its equation form. However, artificial neural network (ANN) does not need a specific equation form. Instead of that, it needs enough input-output data. Also, it can continuously re-train the new data, so that it can conveniently adapt to new data. Therefore, the purpose of this paper is to develop the I-PreConS (Intelligent system for PREdiction of CONcrete Strength using ANN) that provides in-place strength information of the concrete to facilitate concrete form removal and scheduling for construction.

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An Experimental Study on the Verification of Prediction System of Concrete Strength Using Artificial Neural Networks (인공신경망을 이용한 강도추정 시스템의 검증에 관한 실험적 연구)

  • Song Min Seob;Park Jong Ho;Kim Kab Soo;Jang Jong Ho;Lim Jae Hong;Kim Moo Han
    • Proceedings of the Korea Concrete Institute Conference
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    • 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
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    • pp.446-449
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    • 2004
  • Traditional prediction models have been developed with a fixed equation from based on the limited number of data and parameters. If new data is quite different from original data, then the model should update not only its coefficients but also its equation form. However, artificial neural network dose not need a specific equation form. Instead of that, it needs enough input-output data. Also, it can continuously re-train the new data, so that it can conveniently adapt to new data. Therefore, the purpose of this study is to verify faith and application of prediction system of concrete strength using artificial neural networks through mock-up test.

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Effect of Carbonation Threshold Depth on the Initiation Time of Corrosion at the Concrete Durability Design (콘크리트의 내구성 설계시 탄산화 임계깊이가 철근부식 개시시기에 미치는 영향에 관한 연구)

  • Yang, Jae-Won;Lee, Sang-Hyun;Song, Hun;Lee, Han-Seung
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 한국건축시공학회 2010년도 춘계 학술논문 발표대회 1부
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    • pp.229-230
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    • 2010
  • The Carbonation, one of the main deterioration factors of concrete, reduces capacity of members with providing rebar corrosion environment. Consequently it suggested standards of all countries of world, carbonation depth prediction equation of respective researchers and time to rebar corrosion initiation. As a result of carbonation depth prediction equation calculation, difference of time to rebar corrosion initiation is 149 years and difference of carbonation depth prediction equation is 162 years when water cement ratio is 50%. So a study on rebar corrosion with carbonation depth will need existing reliable data and verifications by experiment.

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Thermal Stress Analysis for Life Prediction of Power Plant Turbine Rotor (발전용 터빈 로우터의 수명예측을 위한 열응력 해석)

  • 임종순;허승진;이규봉;유영면
    • Transactions of the Korean Society of Mechanical Engineers
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    • 제14권2호
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    • pp.276-287
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    • 1990
  • In this paper research result of transient thermal stress analysis of power plant turbine rotors for life prediction under severs operating conditions is presented. Galerkin's recurrence scheme is used for numerical solution of discretized FEM equation of transient heat conduction equation. Boundary conditions for the equation and operating conditions are intensively investigated for accurate life prediction of turbine rotors in operation. A computer program for on-site application is developed and tested. Distribution of thermal stress in turbine rotors during various operating condition is analyzed with the program and it is found that the peak thermal stress appears during cold stage conditions at the first stage of high pressure rotors.

Prediction and Analysis of Fracture Strength for Surface Flawed Laminates (표면 손상을 입은 적층판의 강도 예측 및 분석)

  • Choi D. H.;Hwang W.
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 한국복합재료학회 2004년도 춘계학술발표대회 논문집
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    • pp.275-278
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    • 2004
  • In this paper, the fracture strength of the surface damaged laminates was predicted by applying the fracture strengths of the unflawed and flawed laminates. For prediction, the theoretical equation about the fracture strength of laminates was simplified applying classical laminate theory and was applied to the surface damaged laminates. Lagace's and Tsai's experimental data were used for verifying the theoretical equation. Moreover, to verify the theoretical prediction, an experiment was performed. Surface unflawed laminate and flawed laminates were fabricated and the experiments were made and these results were compared with theoretical predictions. The specimens' fiber direction was same to the tensile direction and the theoretical predictions and the experimental results were showed good agreement. Therefore, by this equation, the fracture strength of structures made of composites will be able to be predicted when the surface of the structures was damaged.

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Prediction of 2-Dimensional Unsteady Thermal Discharge into a Reservoir (온수의 표면방출에 의한 2차원 비정상 난류 열확산 의 예측)

  • 박상우;정명균
    • Transactions of the Korean Society of Mechanical Engineers
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    • 제7권4호
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    • pp.451-460
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    • 1983
  • Computational four-equation turbulence model is developed and is applied to predict twodimensional unsteady thermal surface discharge into a reservoir. Turbulent stresses and heat fluxes in the momentum and energy equations are determined from transport equations for the turbulent kinetic energy (R), isotropic rate of kinetic energy dissipation (.epsilon.), mean square temperature variance (theta. over bar $^{2}$), and rate of destruction of the temperature variance (.epsilon. $_{\theta}$). Computational results by four-equation model are favorably compared with those obtained by an extended two-equation model. Added advantage of the four-equation model is that it yields quantitative information about the ratio between the velocity time scale and the thermal time scale and more detailed information about turbulent structure. Predicted time scale ratio is within experimental observations by others. Although the mean velocity and temperature fields are similarly predicted by both models, it is found that the four-equation model is preferably candidate for prediction of highly buoyant turbulent flows.