• Title/Summary/Keyword: reliability Index(B)

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Relations of Safety Factor and Reliability Index for Pile Load Capacity (말뚝 기초지지력에 대한 안전율과 신뢰도지수 평가)

  • Kim, Dae-Ho;Lee, Jun-Hwan
    • Proceedings of the Korean Geotechical Society Conference
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    • 2006.03a
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    • pp.466-475
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    • 2006
  • Reliability analysis between safety factor and reliability index for driven and bored pile load capacity was analyzed in this study. 0.1B, Chin, De Beer, and Davisson's methods were used for determining pile load capacity by using load-settlement curve from pile load test. Each method define ultimate, yield and allowable pile load capacities. LCPC method using CPT results was performed for comparing with results of pile load test. Based on FOSM analysis using load factors, it is obtained that reliability indices for ultimate pile load capacity were higher than those of yield and allowable condition. Present safety factor 2 for yield and allowable load capacities are not enough to satisfy target reliability index $2.0\sim2.5$. However, it is sufficient for ultimate pile load capacity using safety factor 3.

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Development of Bridge Inspection Reliability and Improvement Strategy (교량 점검신뢰도 분석법 개발과 향상방안)

  • Jeong, Yo-Seok;Kim, Woo-Seok;Lee, Il-Keun;Lee, Jae-Ha
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.20 no.5
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    • pp.50-57
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    • 2016
  • The present study proposed three inspection reliability indices which compared inspection results evaluated at in-depth(routine) inspection and in-depth safety inspection; Nominal inspection reliability index, Real inspection reliability index, and DS nominal inspection reliability index. The methods to improve the inspection reliability were also proposed. Since bridge inspection process is critical to ensuring the safety of bridges and identifying repair and maintenance needs, the quality of the inspection data produced from the inspection process is very important. Consequently, the inspection reliability indices were suggested to evaluate quality of current inspection practices. Specifically, approximately 85% of inspection errors evaluated by the DS nominal inspection reliability index are within 1 rating grade(equal to or less than damage score ${\pm}0.1$). In order to improve the inspection reliability, transportation agency should implement QC(Quality Control) practices and develop professional expertises of inspectors by higher requirements for inspectors, on-off line inspection training and etc.

Suggestion for Train Vibration Equations based on Change in Track System (궤도구조 변경에 따른 열차 진동 추정식 제안)

  • 김응록;박연수;강성후;박선준;김흥기
    • Journal of the Korean Society for Railway
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    • v.5 no.1
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    • pp.48-54
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    • 2002
  • This research estimated decreased vibration level as quantitative according to change of track system on Seoul Subway Line No. 1 from existing ballasted track system(Pandrol type clip) to concrete track system(Youbgdan type isolation rubber clip). Following change to concrete system, vibration level at tunnel floor decreased between 4-8dB(V). Vibration equations suggested in this paper consider the velocity of train and can estimate quantitative vibration response. These are divided by ultimate limit state($\beta$=0), serviceability limit state($\beta$=1.28) and safety state($\beta$=3), respectively. The reliability index, $\beta$=0, means 50% data line obtained by least squares best-fit line. The reliability index $\beta$=1.28 and 3 represent boundaries below 90% and 99.9% respectively.

Reliability analysis of a mechanically stabilized earth wall using the surface response methodology optimized by a genetic algorithm

  • Hamrouni, Adam;Dias, Daniel;Sbartai, Badreddine
    • Geomechanics and Engineering
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    • v.15 no.4
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    • pp.937-945
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    • 2018
  • A probabilistic study of a reinforced earth wall in a frictional soil using the surface response methodology (RSM) is presented. A deterministic model based on numerical simulations is used (Abdelouhab et al. 2011, 2012b) and the serviceability limit state (SLS) is considered in the analysis. The model computes the maximum horizontal displacement of the wall. The response surface methodology is utilized for the assessment of the Hasofer-Lind reliability index and is optimized by the use of a genetic algorithm. The soil friction angle and the unit weight are considered as random variables while studying the SLS. The assumption of non-normal distribution for the random variables has an important effect on the reliability index for the practical range of values of the wall horizontal displacement.

Reliability evaluation of steel truss bridge due to traffic load based on bridge weigh-in-motion measurement

  • Widi Nugraha;Indra Djati Sidi;Made Suarjana;Ediansjah Zulkifli
    • Structural Monitoring and Maintenance
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    • v.9 no.4
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    • pp.323-336
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    • 2022
  • Steel truss bridge is one of the most widely used bridge types in Indonesia. Out of all Indonesia's national roads, the number of steel truss bridges reaches 12% of the total 17,160 bridges. The application of steel truss bridges is relatively high considering this type of bridge provides advantages in the standardization of design and fabrication of structural elements for typical bridge spans, as well as ease of mobilization. Directorate of Road and Bridge Engineering, Ministry of Works and Housing, has issued a standard design for steel truss bridges commonly used in Indonesia, which is designed against the design load in SNI 1725-2016 Bridge Loading Standards. Along with the development of actual traffic load measurement technology using Bridge Weigh-in-Motion (B-WIM), traffic loading data can be utilized to evaluate the reliability of standard bridges, such as standard steel truss bridges which are commonly used in Indonesia. The result of the B-WIM measurement on the Central Java Pantura National Road, Batang - Kendal undertaken in 2018, which supports the heaviest load and traffic conditions on the national road, is used in this study. In this study, simulation of a sequences of traffic was carried out based on B-WIM data as a moving load on the Australian type Steel Truss Bridge (i.e., Rangka Baja Australia -RBA) structure model with 60 m class A span. The reliability evaluation was then carried out by calculating the reliability index or the probability of structural failure. Based on the analysis conducted in this study, it was found that the reliability index of the 60 m class Aspan for RBA bridge is 3.04 or the probability of structural failure is 1.18 × 10-3, which describes the level of reliability of the RBA bridge structure due to the loads from B-WIM measurement in Indonesia. For this RBA Bridge 60 m span class A, it was found that the calibrated nominal live load that met the target reliability is increased by 13% than stated in the code, so the uniform distributed load will be 7.60 kN/m2 and the axle line equivalent load will be 55.15 kN/m.

Reliability of Scapular Downward Rotation Measurement in Subjects With Scapular Downward Rotation Syndrome

  • Choi, Woo-Jeong;Lee, Ji-Hyun;Jeong, Hyo-Jung;Yoon, Tae-Lim;Cynn, Heon-Seock
    • Physical Therapy Korea
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    • v.21 no.3
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    • pp.73-79
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    • 2014
  • The purposes of the current study were to (1) estimate the inter-rater agreement for visual assessment of scapular downward rotation (SDR), (2) develop the scapular downward rotation index (SDRI) as a method to measure SDR objectively and quantitatively, and (3) analyze the intra- and inter-rater reliability of the SDRI. Twenty subjects with scapular downward rotation syndrome (SDRS) were recruited for this study. The visual assessment and the measurement for the SDRI were conducted by two examiners in two sessions each. The SDRI [$(a-b){\div}a{\times}100$] is calculated with the measurement of two linear distances: One is a perpendicular distance from the root of the scapular spine to the thoracic mid-line (a), and the other is a perpendicular distance from the inferior angle of the scapula to the thoracic mid-line (b). Cohen's kappa coefficient was calculated to estimate the inter-rater agreement for visual assessment. Intra-class correlation coefficients (ICCs) with a 95% confidence interval (CI), the standard error of measurement, and minimal detectable differences were calculated to assess intra- and inter-rater reliability of SDR measurement using the SDRI. The results indicated that the kappa coefficient of inter-rater agreement for visual assessment was fair (${\kappa}=.21$). The intra-rater reliability of SDR measurement using the SDRI was excellent for examiner 1 (ICC=.92, 95% CI=.78~.97) and good for examiner 2 (ICC=.82, 95% CI=.55~.93). The inter-rater reliability was moderate (ICC=.73, 95% CI=.32~.89). These findings showed that SDR measurement using the SDRI for subjects with SDRS may be considered reliable and better than the visual assessment.

Reliability and Validity Tests of Patient Classification System Based on Nursing Intensity (간호강도에 의한 환자분류도구의 신뢰도 및 타당도 검증)

  • Park, Jung-Ho;Kim, Eun-Hye
    • Journal of Korean Academy of Nursing Administration
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    • v.13 no.1
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    • pp.5-16
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    • 2007
  • Purpose: This study is to verify the validity and reliability of classified items and criteria of the patient classification system(PCS) based on Park's definition of nursing intensity. Methods: An expert group of 8 persons verified the content validity of the tools. The 1817 inpatients at a tertiary hospital in Seoul, Korea were classified into 4 groups according to two tools for verifying concurrent validity and interraters' reliability. These verifications were performed from September to October, 2004. Results: Nursing domains of the tools have been divided into 12 items: hygiene, nutrition, elimination, exercise & activity, education & counseling, emotional support, communication & consciousness, treatment & examination, medication, measurement & observation, coordination of multidisciplinary team, admission & discharge & transfer management. Content validity was verified by the content validity index(above 0.75 in all 12 areas). Interraters' reliability was no significant difference in the results of the patient classification between the two raters(A group 93.75%. B group 88.24%). Concurrent validity was also verified by the agreement of two tools(73.7%). Conclusion: These results showed that the reliability and validity of the PCS based on the nursing intensity were verified. These will use an data for nursing productivity in the future.

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Relations of Safety Factor and Reliability for Pile Load Capacity (말뚝 기초지지력에 대한 안전율과 신뢰도지수 평가)

  • Kim, Dae-Ho;Kim, Min-Ki;Hwang, Sung-Uk;Park, Young-Hwan;Lee, Jun-Hwan
    • Journal of the Korean Geotechnical Society
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    • v.22 no.11
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    • pp.65-73
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    • 2006
  • Reliability between safety factor and reliability index for driven and bored pile load capacity was analyzed in this study. 0.1B, Chin, De Beer, and Davisson's methods were used for determining pile load capacity by using load-settlement curve from pile load test. Each method defines ultimate yield and allowable pile load capacities. LCPC method using CPT results was performed for comparing results of pile load test. Based on FOSM analysis using load factors, it is obtained that reliability indices for ultimate pile load capacity were higher than those of yield and allowable condition. Present safety factor 2 for yield and allowable load capacities is not enough to satisfy target reliability index $2.0{\sim}2.5$. However, it is sufficient for ultimate pile load capacity using safety factor 3.

Analysis of Probabilities of Failure and Partial Safety Factors of Armor Units on Tranding and Coastal Harbors (무역항 및 연안항 피복재의 파괴확률과 부분안전계수 해석)

  • Lee, Cheol-Eung;Park, Dong-Heon
    • Journal of Industrial Technology
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    • v.28 no.B
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    • pp.157-165
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    • 2008
  • Level II AFDA and Level III MCS reliability models are applied to analyze the stability of armor units on trading and coastal harbors in Korea. Hudson's formula and Van der Meer's formula are used in this reliability analysis. Also, probability density functions of reliability index and probability of failure are derived by the additional analysis. In addition, the partial safety factors of all harbors related to armor units can be straightforwardly evaluated by the inverse-reliability method. The upper and lower limits and average level of partial safety factors can be statistically investigated with the results of all cases applied in this paper. Therefore, it may be possible to design armor units of new breakwaters including the uncertainty of random variable and target level by using the present results.

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Interrater Reliability of Upper Extremity Function Assessment on Stroke (뇌졸중 환자에 대한 상지기능 평가도구의 검사자간 신뢰도)

  • Hwang, Seong-Soo;Kim, Pu-Reum;Won, Ji-In;Yoo, Seon-Ju;Yoon, Jun-Byung;Lee, Keun-Woo;Lee, Wang-Jae
    • PNF and Movement
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    • v.10 no.1
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    • pp.1-7
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    • 2012
  • Purpose : To verify the interrater reliability of upper extremity function assessment among three tools(Wolf motor function test, Motor assessment scale, Fugl-meyer assessment scale). Methods : The subjects of this study 40 (20 was physical therapists and 20 was physical therapy students). For the test one patients with chronic hemiparesis after stroke participated in the study. The Wolf Motor Function Test consists of 16 functional tasks. The motor assessment scale consists of 3 functional tasks. The fugl-meyer assessment scale consists of 8 functional tasks. All test sessions were videotaped and scored by 40 subjects. Analysis : The data was analysis by SPSS PC 14.0 with Cronbach alpha Coefficients, intraclass Correlation Coefficients Kendall tau-b value. Results : WMFT was highly scored in Cronbach's value, Cronbach's ${\alpha}=0.819$ that means high interrater reliability among assessment. WMFT was highly scored all items in p-value except one item, that means high p-value between therapists and students. WMFT was highly scored in Intrarater correlation coefficient (ICC) = 0.79, that means high interrater reliability of each examination item. WMFT was low index of coincidence from all items, MAS was low index of coincidence from a tim and FMA was low index of coincidence from 4 items. Conclusion : The interrater reliability of WMFT were compared with MAS, FMA and highly verified. WMFT can be more useful tool among upper extremity function assessment.