• Child Health Nursing Research
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• 제18권2호
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• pp.76-84
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• 2012

Purpose: This study was done to develop a cell phone addiction scale for Korean children. Methods: The process included construction of a conceptual framework, generation of initial items, verification of content validity, selection of secondary items, preliminary study, and extraction of final items. The participants were 268 children from grades 4 to 6 in two urban elementary schools. Construct validity, internal consistence reliability, and split-half reliability were used to analyze the data. Results: Nine items were categorized into 2 factors explaining 61.29% of total variance. The factors were labeled as obsessive compulsion (6 items) and dependency (3 items). Cronbach's alpha coefficient for the 9 items was .87, and Spearman-Brown coefficient was .83. Scale scores identified children as high risk users, at risk users, or average users by standard scores. Conclusion: The above findings indicate that the cell phone addiction scale for children has good validity and reliability when used with Korean children.

• Journal of Preventive Medicine and Public Health
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• 제55권4호
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• pp.334-341
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• 2022

Objectives: This study was conducted to develop the Mobility to Participation Assessment Scale for Stroke (MPASS) and assess its content validity, internal consistency, inter-rater and intra-rater reliability, and convergent validity in people with stroke living in the community. Methods: The MPASS was developed using published data on mobility-related activity and participation timing in elderly individuals, and then reviewed by community physical therapists. Content validity was established by reaching a consensus of experienced physical therapists in a focus group. The MPASS was scored for 32 participants with stroke (mean age 61.75±4.92 years) by 3 individual testers. Reliability was examined using the intraclass correlation coefficient (ICC), internal consistency using the Cronbach alpha coefficient (α), and convergent validity using the Pearson correlation coefficient (r) to compare the MPASS to the Modified Rivermead Mobility Index as a referent test of mobility. Results: The MPASS consists of 8 items, and its scoring system provides information on the ability of people with stroke to reach a movement level enabling them to live in society, including interactions with other people and safe living in the community. The interrater and intra-rater reliability were excellent (ICC, 0.948; 95% confidence interval [CI], 0.893 to 0.982 and ICC, 0.967; 95% CI, 0.933 to 0.989, respectively). Internal consistency was good (α=0.877). The convergent validity was moderate (r=0.646; p<0.001). Conclusions: The newly developed MPASS showed acceptable construct validity and high reliability. The MPASS is suitable for use in people with stroke, especially those who have been discharged and live in the community with the ability to initiate sitting.

• 한국전기전자재료학회논문지
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• 제20권4호
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• pp.352-356
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• 2007

The Ni/Cr/Al/Cu (51/41/4/4 wt%) thin films were deposited by using DC magnetron sputtering method for the application of the resistors having low TCR (temperature coefficients of resistance) and high resistivity from the former printed-results[3]. The TCR values measured on the as-deposited thin film resistors were less than ${\pm}10\;ppm/^{\circ}C$ and $-6{\sim}+1\;ppm/^{\circ}C$ after annealing and packaging process. The TCR values were $-3{\sim}1\;ppm/^{\circ}C$ (ratio of variation : about 0.02 %) and $-30{\sim}20\;ppm/^{\circ}C$ (ratio of variation : about $0.5{\sim}1\;%$) for the thermal cycling and PCT (pressure cooker test), respectively. It was confirmed that the reliability properties of the thin film resistor were good for electronic components.

• 디지털산업정보학회논문지
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• 제7권4호
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• pp.7-14
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• 2011

Infinite failure NHPP models presented in the literature exhibit either constant, monotonic increasing or monotonic decreasing failure occurrence rate per fault (hazard function). This infinite non-homogeneous Poisson process is model which reflects the possibility of introducing new faults when correcting or modifying the software. In this paper, polynomial hazard function have been proposed, which can efficiency application for software reliability. Algorithm for estimating the parameters used to maximum likelihood estimator and bisection method. Model selection based on mean square error and the coefficient of determination for the sake of efficient model were employed. In numerical example, log power time model of the existing model in this area and the polynomial hazard function model were compared using failure interval time. Because polynomial hazard function model is more efficient in terms of reliability, polynomial hazard function model as an alternative to the existing model also were able to confirm that can use in this area.

• 한국전기전자재료학회논문지
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• 제18권8호
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• pp.685-689
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• 2005

In the fabrication and design of MLCCs (Multilayer Ceramic Capacitors) with Ni inner electrode for medium and high voltage, reliability and dielectric breakdown mode have been investigated. For thickness of green sheet, the relationship between the rated voltage versus the thickness of green sheet. Increasing the thickness of green sheet increases the dielectric breakdown voltage. However, a practical limit to this linear relationship occurs at 30 urn and above. As the thickness of green sheet increased, dielectric breakdown voltage and weibull coefficient is increased, but abruptly decrease at 30 urn and 36 urn. When 24 urn of green sheet thickness, weibull coefficient and dielectric breakdown voltage were 13.58 and 70 V/um respectively. The results enabling the MLCCs to demonstrate high levels of reliability at medium and high voltage.

• 대한가정학회지
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• 제36권6호
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• pp.95-108
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• 1998

This study is the second study which was aimed to validate the Infant/ Toddler Environment Rating Scale(ITERS). The test-retest reliability included 10 infant/toddler classes among 30 national/public and private child care centers in Inchon city which had been observed in the first validation study. The Spearman's correlation coefficient for test-retest reliability was ranged from .52 to .84. In addition, two raters observed 10 family day care centers in Inchon city, where two observers independently rated each centers on the ITERS during a single visit. The Spearman's correlation coefficient for interrater reliability was ranged from.72 to .99 For the second measure of content validity, experts who were working in day care centers and who were graduate students, lecturers, or professors majoring child studies rated the appropriateness of each ITERS items for the provision of high-quality programs for infants and toddlers, using a 1(low) to 5(high) scale. The mean rating was ranged from 2.52 to 4.52. In sum, when the rating scores were analyzed by the type of child care centers, national/public child care centers have better quality than private or family child care centers.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 C
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• pp.1073-1075
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• 1999

This Paper Presents the process of load management for distribution Pole transformer at KEPCO. The purpose of this process is to establish reasonable peak load forecasting and prevention of Pole transformer damages caused by overload through the investigation of correlation coefficient for recent load characteristics. In this Paper, we newly proposed more reliable correlation coefficient using improved method and verified its reliability in various ways.

• E2M - 전기 전자와 첨단 소재
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• 제9권3호
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• pp.246-250
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• 1996

In optical soliton transmission systems with nonlinear dispersive materials, which is utilized for ultra-long and high bit rate transmission, it is shown that the value of initial time difference between adjacent solitons is analyzed for optimum bit rate. The method is inducted by uncorrelation condition with minimum interaction forces in initial covariance coefficient between adjacent solitons. When the initial time difference is 6 times of soliton pulse width by the results, it is shown that the reliability is maintained with more than 90% within transmission length of soliton period. multiplied by 93.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집A
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• pp.262-267
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• 2001

In this study, the Reliability of degraded steam turbine blade was evaluated using the limited fatigue data. The statistical estimation of limited fatigue data implies that some unknown uncertainties which may be involved in fatigue reliability analysis. Therefore, an appropriate distribution in the fatigue strength was determined by the characteristic distribution - linear correlation coefficient, fatigue physics, error parameter. 3-parameter Weibull distribution is the most appropriate distribution to assume for infinite region. The load applied on the blade is mainly tensile. The maximum Von-Mises stress is 219.4 MPa at the steady state service condition. The failure probability($F_p$) derived from the strength-stress interference model using Monte carlo simulation under variable service condition is 0.25% at the 99.99% confidence level.

• Geomechanics and Engineering
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• 제12권2호
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• pp.313-326
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• 2017

Based on the reliability theory and limit analysis method, the roof stability of a shallow tunnel is investigated under the condition of surface settlement. Nonlinear Hoek-Brown failure criterion is adopted in the present analysis. With the consideration of surface settlement, the internal energy and external work are calculated. Equating the rate of energy dissipation to the external rate of work, the expression of support pressure is derived. With the help of variational approach, a performance function is proposed to reliability analysis. Improved response surface method is used to calculate the Hasofer-Lind reliability index and the failure probability. In order to assess the validity of the present results, Monte-Carlo simulation is performed to examine the correctness. Sensitivity analysis is used to estimate the influence of different variables on reliability index. Among random variables, the unit weight significantly affects the reliability index. It is found that the greater coefficient of variation of variables lead to the higher failure probability. On the basis of the discussions, the reliability-based design is achieved to calculate the required tunnel support pressure under different situations when the target reliability index is obtained.