• Journal of Applied Reliability
• /
• v.16 no.3
• /
• pp.245-253
• /
• 2016

Purpose: The purpose of this study is to measure the reliability of complex equipment. Reliability of product is one of the most important factor to achieve competitiveness in the market. While there were many researches for assessing the reliability on components and modules, research on quantitative assessment tool for equipment with many component was little because of equipment's complexity. Methods: In this article, we developed index to assess reliability management system by using IEC 60300 and Reliability Management Tool-kit. With MIR and BARS, we developed reliability index clauses relevant to reliability activities and found weight factor for each clause by survey on experts. Results: The results of this study were as follows; reliability index that can assess both management side and technology side of the company was developed. Conclusion: Using this index, we assessed the reliability of a manufacturing equipment and found out the current reliability level of the manufacturing equipment, and derived improvement points.

• International Journal of Highway Engineering
• /
• v.18 no.4
• /
• pp.77-82
• /
• 2016

PURPOSES : This paper proposes a reliability index for the safety evaluation of freeway sections. It establishes a reliability index as a safety surrogate on freeways considering speeds and speed dispersions. METHODS : We collated values of design elements including radii, curve lengths, vertical slopes (absolute values), superelevations, and vertical slopes from seven freeway sections in Korea. We also collected data about driving speeds, traffic accidents, and their deviations. We established a reliability index using these variables. RESULTS : The average radii, curve lengths, and superelevations are highly correlated with the incidence of traffic accidents. Deviations in radius and curve lengths show an especially high correlation. The reliability index, derived from speed and speed dispersions of the seven freeway sections, also correlated highly with accidents with a correlation index of 0.63. CONCLUSIONS : Since the reliability index obtained from speed and speed dispersions are highly correlated with traffic accidents, we conclude that a reliability index can be a safety surrogate on freeways considering speeds and speed dispersions together in terms of design and operational levels.

• Structural Engineering and Mechanics
• /
• v.62 no.3
• /
• pp.365-372
• /
• 2017

Reliability analysis is a probabilistic approach to determine a safety level of a system. Reliability is defined as a probability of a system (or a structure, in structural engineering) to functionally perform under given conditions. In the 1960s, Basler defined the reliability index as a measure to elucidate the safety level of the system, which until today is a commonly used parameter. However, the reliability index has been formulated based on the pivotal assumption which assumed that the considered limit state function is normally distributed. Nevertheless, it is not guaranteed that the limit state function of systems follow as normal distributions; therefore, there is a need to define a new reliability index for no-normal distributions. The main contribution of this paper is to define a sophisticated reliability index for limit state functions which their distributions are non-normal. To do so, the new definition of reliability index is introduced for non-normal limit state functions according to the probability functions which are calculated based on the convolution theory. Eventually, as the state of the art, this paper introduces a simplified method to calculate the reliability index for non-normal distributions. The simplified method is developed to generate non-normal limit state in terms of normal distributions using series of Gaussian functions.

• International Journal of Knowledge Content Development & Technology
• /
• v.9 no.2
• /
• pp.65-89
• /
• 2019

This study has the aim of developing an evaluation index that can help evaluate the reliability of the information resources of institutions retaining humanities assets for the purposes of laying out the foundation for providing one-stop portal service for humanities assets. To this end, the evaluation index was derived through the analysis of previous research, case studies, and interviews with experts, the derived evaluation index was then applied to the humanities assets retaining institutions to verify the utility. The institutional information resources' reliability evaluation index consisted of the two dimensions of the institutions' own reliability evaluation index. The institution provided a service and system evaluation index. The institutions' own reliability evaluation index consisted of 25 points for institutional authority, 25 points for data collection and construction, 30 points for data provision, and 20 points for appropriateness of data, for a total of 100 points, respectively. The institution provided service and system evaluation indexes consisting of 25 points for information quality, 15 points for appropriateness (decency), 15 points for accessibility, 20 points for tangibility, 15 points for form, and 10 points for cooperation, for the total of 100 points, respectively. The derived evaluation index was used to evaluate the utility of 6 institutions representing humanities assets through application. Consequently, the reliability of the information resources retained by the Research Information Service System (RISS) of the Korea Education & Research Information Service (KERIS) turned out to be the highest.

• Earthquakes and Structures
• /
• v.8 no.5
• /
• pp.995-1016
• /
• 2015

The reliability or the safety index is a measure of how far a structure is from the state of collapse. Also it defined as the probability that a structure will not fail in its lifetime. Having any increase in the reliability index is typically interpreted as increasing in the safety of structures. On the other hand most of researchers acknowledged that one of the most effective means of increasing both the reliability and the safety of structures is to increase the structural redundancy. They also acknowledged that increasing the number of vertical seismic framing will make structural system more reliable and safer against stochastic events such as earthquakes. In this paper the reliability index and the behavior factor of a numbers of three dimensional RC moment resisting frames with the same story area, equal lateral resistant as well as different redundancy has been evaluated numerically using both deterministic and probabilistic approaches. Study on the reliability index and the behavior factor in the case study models of this research illustrated that the changes of these two factors do not have always the same manner due to the increasing of the structural redundancy. In some cases, structures with larger reliability index have smaller behavior factor. Also assuming the same ultimate lateral resistance of structures which causes an increase to a certain level of redundancy can enhance behavior factor of structures. However any further increase in the redundancy of that certain level might decrease the behavior factor. Furthermore, the results of this study illustrate that concerning any increase in the structural redundancy will make the reliability index of structure to be larger.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2004.11a
• /
• pp.433-436
• /
• 2004

The safety of buildings is generally estimated by analyzing a plane frame ignoring a minor bending moment. In this paper, uncertainties of reinforced concrete shear wall subjected to a biaxial bending are considered. First, major parameters are selected from all parameters of general shear wall design to perform a reliability analysis in their practical ranges, means and standard derivations of selected design parameters for the reliability analysis are calculated by a data mining as a simulation method. The bi-section method is used to find inclined neutral axis and its limit state using MATLAB subjected to the concept on strength design method. The reliability index $\beta$ as a safety index is calculated based on AFOSM(Advanced First-Order Second Moment) method. Also, if target reliability index $\beta_T$ is decided by an engineer an amount of reinforcement can be calculated by subtracting the reliability index $\beta$ from the target reliability index $\beta_T$.

• Journal of the Korean Society of Physical Medicine
• /
• v.8 no.4
• /
• pp.573-582
• /
• 2013

PURPOSE: The purpose of this study was to establish the reliability and validity of the Wheelchair User's Shoulder Pain Index (WUSPI), which was translated into Korean for long-term wheelchair users. This index measured 15 functional activities, including transfer, self-care, wheelchair mobility and general activities. METHODS: To assess test-retest reliability, 23 long-term wheelchair users completed this self-administered index twice within the same day. Reliability was determined by the intraclass correlation coefficient (ICC), and Cronbach's alpha was used to measure internal consistency. To examine concurrent validity, 21 long-term wheelchair users completed the questionnaire, and we examined the correlation between the index score and the shoulder range of motion measurements. RESULT: The results showed that the intraclass correlation for test-retest reliability of the total index score ranging from .88 to .99 was good to excellent. Additionally, Cronbach's alpha was .96. The internal consistency indicated excellent. Concurrent validity showed negative correlations of total index score to range of motion measurements of shoulder flexion (rho=-.58), extension (rho=-.09), abduction (rho=-.59), external rotation (rho=-.07) and internal rotation (rho=-.3), suggesting a relationship of total index score to loss of shoulder range of motion. CONCLUSION: The Korean WUSPI shows not only high reliability and internal consistency, but also concurrent validity with loss of shoulder flexion and abduction.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 1989.10a
• /
• pp.34-39
• /
• 1989

Recent trends in design standards development have encouraged the use of probabilistic limit sate design concepts. Reliability analysis adopted in those advanced countries have the potentials that they afford for symplifying the design Process arid placing it on a consistent reliability based for various construction materials. This study is proposed in the reliability analysis of plane frame structures using second-order moment method(Level-II they). Lind-Hasofer's minimum distance method is use in the derivation of an mathematical algorithm as well as an determination of Correlation cofficients, reliability index and total reliability index depending on the multiple failure modes. In addition. This study is employed as a practical tool for the approximate reliability analysis. Results of the numerincal analysis showed that the difference between the reliability index of the failure probability of the multiple failure modes and the total reliability index of the failure probability with the simultaneous failure modes deviated nearly 3∼10% depending on tile performance functions.

• Geomechanics and Engineering
• /
• v.12 no.2
• /
• pp.313-326
• /
• 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.

• Journal of the Korean Society of Physical Medicine
• /
• v.18 no.2
• /
• pp.93-101
• /
• 2023

PURPOSE: The Western Ontario and McMaster Universities Arthritis (WOMAC) index has been used to measure the outcome of total knee replacement (TKR), but studies on its reliability and validity are limited. The present study examined the reliability and validity of this index for patients with knee osteoarthritis who underwent TKR. METHODS: Seventy-one inpatients and outpatients who underwent bilateral TKR for knee osteoarthritis were included in this study. The pain assessment scale and WOMAC index were used to evaluate the participants every two weeks to examine the test-retest reliability, internal consistency, and construct validity. RESULTS: The test-retest reliability scores for pain, stiffness, and physical function were .75-.92, .85-.90, and .75-.95, respectively. The corresponding intraclass correlation coefficients were .75-.88, .76-.88, and .71-.95, respectively. The internal consistency score in the first and second examinations was .92. Furthermore, the construct validity scores for pain, stiffness, and physical function were .83, .41, and .58, respectively. CONCLUSION: The application of the WOMAC index in patients who underwent TKR showed high test-retest reliability and internal consistency with the use of the WOMAC index and good validity with the use of the pain assessment scale.