• 제목/요약/키워드: Estimating the validity

검색결과 233건 처리시간 0.023초

Development and application of the sodium index to estimate and assess sodium intake for Korean adults

  • Lee, Yeon-Kyung;Hyun, Taisun;Ro, Heekyong;Heo, Young-Ran;Choi, Mi-Kyeong
    • Nutrition Research and Practice
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    • 제16권3호
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    • pp.366-378
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    • 2022
  • BACKGROUND/OBJECTIVES: The purpose of this study was to develop a sodium index, which is a tool for estimating and assessing sodium intake easily and quickly, to assist in the prevention of various diseases induced by excess sodium intake in Korean adults. SUBJECTS/METHODS: The 24-h urine collection and dietary behavior surveys were performed on 640 healthy people in 4 regions of South Korea, and an equation for the estimation of 24-h sodium intake was developed. The validity and reliability of the equation were verified with 200 adults. The sodium index was developed by converting the estimated sodium intake using the equation. Finally, the sodium intake status of 1,600 adults was assessed using the sodium index. RESULTS: The equation included sex, age, body mass index, eating habit and dietary behaviors related to sodium intake. In validity test of the equation, the mean bias between sodium intake using 24-h urine analysis and using the equation from the Bland-Altman plots was -1.5 mg/day. The sensitivity and specificity of the equation for estimation of sodium intake were 80.5% and 64.4%, respectively. In the reliability test of the equation, there was no significant difference between the first and second sodium intakes calculated using the equations, and Spearman's correlation coefficient between the 2 sodium intakes was 0.98. Sodium intake can be assessed as 'very moderate' for 75-100 on the sodium index, 'moderate' for 100-150, 'careful' for less than 75 or 150-200, and 'severe' for 250 or more. When sodium intake was assessed using the sodium index in 1,600 subjects, 54.3% and 24.3% of the subjects were assessed to be in the 'careful' and 'severe' categories, respectively. CONCLUSIONS: Using a simple questionnaire, the sodium index can be used to monitor and assess sodium intake status, assisting in nutrition education and counseling in a large population.

소아 환자 분류도구의 개발 (Development of Pediatric Patient Classification System)

  • 권미경;박지선;박현미;강현주;우정에;이혜연;김예슬;심미영
    • 임상간호연구
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    • 제26권2호
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    • pp.175-185
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    • 2020
  • Purpose: This study was performed to develop a valid and reliable Pediatric Patient Classification System (PPCS). Methods: The study was conducted in a children's hospital which included various ward settings. Content validity was analyzed by Delphi method and to verify intraclass correlation reliability, 7 nurse managers and 29 staff nurses classified 216 patients. To verify construct validity, the staff nurses classified 216 patients according to PPCS comparing differences by age, days of stay, type of stay and medical department. Results: The developed PPCS has 12 categories, 55 nursing activities and 80 criterions. High agreement among nurses (r=.90) suggested substantial reliability. Construct validity was verified by comparing differences in age, days of stay, type of stay and medical department (p<.05). The entire patient group were classified to four groups using PPCS. Conclusion: The findings suggest that PPCS would be a useful tool for estimating nursing demands related to medications and the complexity of pediatric patients.

ISSC-TLP의 운동응답 및 변동장력에 미치는 다방향 불규칙파의 영향 (Effects of the Multi-directional Irregular Waves on the Motion Responses and Tension Variations of ISSC-TLP)

  • 이창호
    • 한국해양공학회지
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    • 제20권4호
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    • pp.70-75
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    • 2006
  • A numerical procedure is described for estimating the effects of the multi-directional irregular waves on the motion responses and tension variations of the ISSC-TLP. The numerical approach is based on a three-dimensional source distribution method and a spectral analysis technique of directional waves. The spectral description for the linear system of ISSC-TLP in the frequency domain is sufficient to completely define the motion responses and tension variations. This is because both the wave inputs and responses are stationary Gaussian random processes, of which the statistical properties in the amplitude domain are well known. The numerical results for the linear motion responses and tension variations in regular waves are compared with the experimental and numerical ones, which are obtained in the literature. The results of comparison confirmed the validity of the proposed approach.

경사진 등온 평판위 의 자연대류 유동 에서의 와류 불안정성 과 열전달 상관관계 (Vortex Instability and Heat Transfer Correlations in the Natural Convection Flow over Inclined Isothermal flat Plates)

  • 최창균;유정열;이형인
    • 대한기계학회논문집
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    • 제8권1호
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    • pp.10-17
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    • 1984
  • The critical conditions marking the onset of thermally induced vortices over an inclined iso-thermal plate are investigated using the linear stability theory. The stability equations are simplified by estimating the orders of magnitude of respective terms. The analysis is carried out under the assumption that for the system of large Prandtl numbers temperature disturbances are initiated within the conventional thermal boundary layer of the basic flow. The stability criteria obtained from the present results agree well with those of the existing quasi-parallel flow models. In addition it is found that the critical conditions generate the heat transfer correlation in good agreement with experiments. Therefore, it is suggested that the validity of existing theoretical models will be reexamined.

축하중을 받는 철근콘크리트 부재의 재령계수식 제안 (Aging Coefficient Formula of Reinforced Concrete Members under Axial Compression)

  • 유재욱;유은종
    • 한국공간구조학회논문집
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    • 제13권4호
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    • pp.67-74
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    • 2013
  • The Age-adjusted effective Modulus Method(AEMM) is one of the methods adopted for the construction stage analysis of concrete structures. The AEMM uses the aging factor to consider the effects of the varying concrete stress. In the aspects of computation time and the accuracy of the results, the AEMM is considered as one of most appropriate methods for construction stage analysis of tall building structures. Previous researches proposed appropriate values of the aging factor in the forms of graphs or using very simple equations. In this paper, an equation for estimating the aging factor as a function of rebar ratio in the section, compressive strength of concrete, notional member dimension, and age of concrete at the load application. The validity of aging factor proposed in this paper were examined by the comparison with the results of step-by step method.

A Study on Plate Bending Analysis Using Boundary Element Method

  • Son, Jae-hyeon;Kim, Yooil
    • 한국해양공학회지
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    • 제36권4호
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    • pp.232-242
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    • 2022
  • This study presents a method for level ice-structure interaction analysis to estimate the fatigue damage of arctic structures by applying plate theory to the behavior of level ice. The boundary element method (BEM), which incurs a lower computational cost than the finite element method (FEM), was introduced to solve the plate bending problem. The BEM formulation was performed by applying the BEM to plate theory. Finally, to check the validity of the proposed method, the BEM results and FEM results obtained using the ABAQUS commercial software were compared. The response results of the BEM analysis agreed well with those of the FEM analysis. Based on the results of the analysis, the BEM approach is considered to be very powerful in level ice-structure interaction analysis for estimating level ice-induced fatigue damage. Further work is being conducted to perform level ice fracture analysis based on the stress field calculated using the boundary element method.

IMPROVEMENT OF CROSS-CORRELATION TECHNIQUE FOR LEAK DETECTION OF A BURIED PIPE IN A TONAL NOISY ENVIRONMENT

  • Yoon, Doo-Byung;Park, Jin-Ho;Shin, Sung-Hwan
    • Nuclear Engineering and Technology
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    • 제44권8호
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    • pp.977-984
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    • 2012
  • The cross-correlation technique has been widely used for leakage detection of buried pipes, and this technique can be successfully applied when the leakage signal has a high signal-to-noise ratio. In the case of a power plant, the measured leakage signals obtained from the sensors may contain background noise and mechanical noise generated by adjacent machinery. In such a case, the conventional method using the cross-correlation function may fail to estimate the leakage point. In order to enhance the leakage estimation capability of a buried pipe in a noisy environment, an improved cross-correlation technique is proposed. It uses a noise rejection technique in the frequency domain to effectively eliminate the tonal noise due to rotating machinery. Experiments were carried out to verify the validity of the proposed method. The results show that even in a tonal noisy environment, the proposed method can provide more reliable means for estimating the time delay of the leakage signals.

무심천 유역에 대한 지하수 함양량의 시공간적 변동성 분석

  • 정일문;김남원;이정우;이병주
    • 한국지하수토양환경학회:학술대회논문집
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    • 한국지하수토양환경학회 2006년도 총회 및 춘계학술발표회
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    • pp.282-285
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    • 2006
  • This study is to present the method for estimating groundwater recharge with temporal-spatial variability using the SWAT model which can represent the heterogeneity of the watershed. The SWAT model can simulate daily surface runoff, evapotranspiration, soil storage, recharge, and groundwater flow within the watershed. The model was applied to Musimcheon watershed located in the upstream of Mihocheon watershed. Hydrological components were determined for the period 2001 - 2004, and the validity of the results was tested by comparing the estimated runoff with the observed runoff data at the outlet of the catchment. The results of temporal and spatial variations of recharge were presented, This study suggests that variations in recharge can be significantly affected by subbasin slope as well as land use changes.

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화자인식을 위한 퍼지-상관차원과 퍼지-리아프노프차원의 평가 (The Evaluation of the Fuzzy-Chaos Dimension and the Fuzzy-Lyapunov Ddimension)

  • 유병욱;박현숙;김창석
    • 음성과학
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    • 제7권3호
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    • pp.167-183
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    • 2000
  • In this paper, we propose two kinds of chaos dimensions, the fuzzy correlation and fuzzy Lyapunov dimensions, for speaker recognition. The proposal is based on the point that chaos enables us to analyze the non-linear information contained in individual's speech signal and to obtain superior discrimination capability. We confirm that the proposed fuzzy chaos dimensions play an important role in enhancing speaker recognition ratio, by absorbing the variations of the reference and test pattern attractors. In order to evaluate the proposed fuzzy chaos dimensions, we suggest speaker recognition using the proposed dimensions. In other words, we investigate the validity of the speaker recognition parameters, by estimating the recognition error according to the discrimination error of an individual speaker from the reference pattern.

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적응 역기전력 추정기와 개선된 순시 무효전력 보상기를 이용한 돌극형 영구자석 전동기의 센서리스 제어 (A Sensorless Control of IPMSM using the Adaptive Back-EMF Estimator and Improved Instantaneous Reactive Power Compensator)

  • 이준민;홍주훈;김영석
    • 전기학회논문지
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    • 제65권5호
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    • pp.794-803
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    • 2016
  • This paper propose a sensorless control system of IPMSM with a adaptive back-EMF estimator and improved instantaneous reactive power compensator. A saliency-based back-EMF is estimated by using the adaptive algorithm. The estimated back-EMF is inputted to the phase locked loop(PLL) and the improved instantaneous reactive power(IRP) compensator for estimating the position/speed of the rotor and compensating the error components between the estimated and the actual position, respectively. The stability of the proposed system is achieved through Popov's hyper stability criteria. The validity of proposed algorithm is verified by the simulations and experiments.