• Title/Summary/Keyword: reliability index profile

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Fuzzy Reliability Analysis Models for Maintenance of Bridge Structure Systems (교량구조시스템의 유지관리를 위한 퍼지 신뢰성해석 모델)

  • 김종길;손용우;이증빈;이채규;안영기
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2003.10a
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    • pp.103-114
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    • 2003
  • This paper aims to propose a method that helps maintenance engineers to evaluate the damage states of bridge structure systems by using a Fuzzy Fault Tree Analysis. It may be stated that Fuzzy Fault Tree Analysis may be very useful for the systematic and rational fuzzy reliability assessment for real bridge structure systems problems because the approach is able to effectively deal with all the related bridge structural element damages in terms of the linguistic variables that incorporate systematically experts experiences and subjective judgement. This paper considers these uncertainties by providing a fuzzy reliability-based framework and shows that the identification of the optimum maintenance scenario is a straightforward process. This is achieved by using a computer program for LIFETIME. This program can consider the effects of various types of actions on the fuzzy reliability index profile of a deteriorating structures. Only the effect of maintenance interventions is considered in this study. However. any environmental or mechanical action affecting the fuzzy reliability index profile can be considered in LIFETIME. Numerical examples of deteriorating bridges are presented to illustrate the capability of the proposed approach. Further development and implementation of this approach are recommended for future research.

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Reliability Analysis Models for Maintenance of bridge structures (교량구조물의 유지관리를 위한 신뢰성 해석 모델)

  • Kim, Jong-Gil;Sohn, Yong-Woo;Lee, Cheung-Bin;Ahn, Young-Ki
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.8 no.3
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    • pp.251-261
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    • 2004
  • Recently, the corrosion and aging of bridge structures are of great concern impractical The uncertainties of the corroded reinforced bars in concrete influence not only the safety of the bridge structures, but also the flexural strength of reinforced concrete members. This paper considers these uncertainties by providing a reliability-based framework and show that the identification of the optimum maintenance scenario is a straightforward process. This is achieved by using a computer pro망am for Life Cycle Cost Analysis of Deteriorating Structures (LCCADS). This program can consider the effects of various types of actions on the reliability index profile of a deteriorating structures.

The Variation of Slope Stability by Ground Water Level in Railway Lines (지하수위에 따른 철도사면의 안정성 변화)

  • Kim, Hyun-Ki;Shin, Min-Ho;Shin, Ji-Soo
    • Proceedings of the KSR Conference
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    • 2008.11b
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    • pp.789-795
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    • 2008
  • Slope stability is affected by various factors. For safety management of slopes, monitoring systems have been widely constructed along railway lines. The representative data from the systems are variations of ground profile such like ground water level and pore water pressure etc. and direct displacement measured by ground clinometer and tension wire sensor. Slopes are mainly effected by rainfall and rainfall causes the decrease of factor of safety(FOS). Because FOS varies linearly by the variation of ground water level and pore pressure, it has a weak point that could not define the time and proper warning sign to secure the safety of the train. In this study, alternative of FOS such as reliability index and probability of failure is applied to slope stability analysis introducing the reliability concept. FOS, reliability index, probability of failure and velocity of probability of failure of the slopes by variation of ground water level are investigated for setting up the specification of safety management of slopes. By executing case study of a slope(ILLO-IMSUNGLI), it is showed to be applied to specification of safety management.

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Data Transition Research to Derive Shape Factor in Analyzing Factors -Centering on the body shape of males in twenties- (요인분석시 형태요인을 도출시키기 위한 자료 변환 연구 - 20대 남성 체형을 중심으로 -)

  • 석혜정;김인숙
    • Journal of the Korean Home Economics Association
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    • v.40 no.2
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    • pp.67-86
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    • 2002
  • The purpose of this research is to offer a method to derive the body shapes and pose factors with resets from analyzing factors by using the measurement values of human body. 297 male subjects in their twenties participated in this study. 54 anthropometric and 35 photographic measurements were taken from each subject. Data is the several typical items selected among items and you have to make an index value by using these typical items and convert it. The index has high correlation with each item, is easy to be measured and is to be used after selecting an important item in designing prototype. With results of analyzing reliability level by each item, correlation and items that factor loading is low, the item that the correlation is high is to be removed within the range that maintains the reliability level. Five factors of the front part and seven factors of the profile came to be derived from this kind of process.

Study on function evaluation tools for stroke patients (뇌졸중(腦卒中) 환자(患者)의 기능평가방법(機能評價方法)에 대(對)한 연구(硏究))

  • Ko, Seong-Gyu;Ko, Chang-Nam;Chox, Ki-Ho;Kim, Young-Suk;Bae, Hyung-Sup;Lee, Kyung-Sup
    • The Journal of Korean Medicine
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    • v.17 no.1 s.31
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    • pp.48-83
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    • 1996
  • Our conclusions for function evaluation tools of Stroke patients are as follows. 1. Evaluating tools of Activities of Daily Living, Katz Index, Barthel Index, Modified Barthel Index have high validity and reliability because of ease of measuring, high accuracy, consistency, sensitivity and sufficient stastistics, but they mainly measure motor function except sense, mentation, language, and social conception. Therefore cerebrovascular disease and brain injury in trauma patients with lacked acknowledgement and sensation, we are not able to apply these tools. 2. PULSES Profile is a useful scale for measuring the patient's over-all status, upper and lower limb functions, sensory components, excretary functions, and intellectual and emotional adaptabilities. It is recognized as a good, useful tool to evaluate patient's whole function. 3. Motor Assessment Scale was designed to measure the progress of stroke patients. The scale was supplemented with upper arm function items. We believe that the Motor Assessment Scale could be a useful evaluation tool with inter-rater reliability ,test-retest reliability. 4. The existing evaluation tools, Katz Index, Barthel Index, Modified Barthel Index, PULSES Profile, Motor Assessment Scale, mainly measured the rehabilitational motor function of sequela of cerebrovascular patients. On the other hand CNS & INH stroke scale can measure cerebrovascular disease patient's neurologic deficits and over-all stautus, which are recognition ability, speech status, motor function, sensory function, activities of daily living. Those scales have been recognized as useful tools to measure function of cerebrovascular disease patients and have increased in use. 5. Every function evaluation tool was recognized to have some validity and inter-rater, test-retest reliability in items of each evaluation tool and total scores of each evaluation tools, but it is thought that none of these scales have been fully validated and proved reliable. Therefore afterward, the development of a highly reliable rating system may best be accomplished by a careful comparison of several tools, using the same patients and the same observers in order to choose the most reliable items from each. 6. Ideal evaluation tools must have the following conditions; (1) It should show the objective functional statues at the same time. (2) It should be repeated consecutively to know changed function status. (3) It should be easy to observe the treatment program. (4) It should have the same result with another rater to help rater exchange information with treatment team members. (5) It should be practical and simple. (6) The patient should not suffer from the observer.

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Development of the Road Profiling System and Evaluation of Korean Roads Roughness Characteristics (도로면 측정 분석 시스템 개발 및 국내 도로면 특성평가 응용 연구)

  • 손성효;허승진
    • Transactions of the Korean Society of Automotive Engineers
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    • v.11 no.3
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    • pp.192-197
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    • 2003
  • The ‘AEIPR’(Accelerometer Established Inertial Profiling Reference) method has been applied to measure the road profile. The dynamic road profiling method using AEIPR has the advantages of cost effectiveness, measuring speed and relatively high reliability. However, it is required to improve the double integration algorithm to get the measurement results with the accuracy of hither level. In the first part of this paper, the effective double integration algorithm is suggested and the ‘Road Profiler’ software is developed on the basis of the algorithm. Road profiling tests are performed using the developed ‘Road Profiler’ system on the specially designed tracks for the durability tests and the various types of pubic roads. Test results are shown and evaluated by the international road evaluation indicies and classification.

A Study on the Severity Control of Unpaved Test Courses (비포장 노면의 가혹도 관리에 관한 연구)

  • Yang, Jin-Saeng;Goo, Sang-Hwa;Lee, Jeong-Hwan;Kang, Do-Kyoung;Lee, Sang-Ho
    • Journal of the Korean Society for Precision Engineering
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    • v.24 no.2 s.191
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    • pp.47-57
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    • 2007
  • The vibration environment essentially companied by vehicle operation on the road is determined by the shape of road surface, which is called profile. In general, the profile and severity of unpaved road is an important issue in the reliability of durability test for vehicles. In order to maintain severity of unpaved road, it is necessary to develop profilometer system. We developed profilometer system which is composed of data processing computer, power unit, air compressor and sensors. This paper focuses on the severity management of unpaved test courses using neural networks. This paper presents the maintenance range for cross-country course in CPG(Chang-won Proving Ground) and the evaluation of similarity degree between unpaved roads.

Estimation of Reliability of Real-time Control Parameters for Animal Wastewater Treatment Process and Establishment of an Index for Supplemental Carbon Source Addition (가축분뇨처리공정의 자동제어 인자 신뢰성 평가 및 적정 외부탄소원 공급량 지표 확립)

  • Pak, JaeIn;Ra, Jae In-
    • Journal of Animal Science and Technology
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    • v.50 no.4
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    • pp.561-572
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    • 2008
  • Responses of real-time control parameters, such as ORP, DO and pH, to the conditions of biological animal wastewater treatment process were examined to evaluate the stability of real-time control using each parameter. Also an optimum index for supplemental carbon source addition based on NOx-N level was determined under a consideration of denitrification rate by endogenous respiration of microorganism and residual organic matter in liquor. Experiment was performed with lab-scale sequencing batch reactor(SBR) and working volume of the process was 45L. The distinctive nitrogen break point(NBP) on ORP-and DO-time profiles, which mean the termination of nitrification, started disappearing with the maintenance of low NH4-N loading rate. Also the NBP on ORP-and DO-time profiles was no longer observed when high NOx-N was loaded into the reactor, and the sensitivity of ORP became dull with the increase of NOx-N level. However, the distinctive NBP was constantly occurred on pH(mV)-time profile, maintaining unique profile patterns. This stable occurrence of NBP on pH(mV)-time profile was lasted even at very high NOx-N:NH4-N ratio(over 80:1) in reactor, and the specific point could be easily detected by tracking moving slope change(MSC) of the curve. Revelation of NBP on pH(mV)-time profile and recognition of the realtime control point using MSC were stable at a condition of over 300mg/L NOx-N level in reactor. The occurrence of distinctive NBP was persistent on pH(mV)-time profile even at a level of 10,000mg/L STOC(soluble total organic carbon) and the recognition of NBP was feasible by tracing MSC, but that point on ORP and DO-time profiles began to disappear with the increase of STOC level in reactor. The denitrfication rate by endogenous respiration and residual organic matter was about 0.4mg/L.hr., and it was found that 0.83 would be accepted as an index for supplemental carbon source addition when 0.1 of safety factor was applied.

Development and validation of Pediatric Weakness Scale (PWS) (소아 허약 검사의 개발과 타당화 연구)

  • Chae, Han;Han, Sang Yun;Cheon, Jin Hong;Kim, Kibong
    • The Journal of Pediatrics of Korean Medicine
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    • v.33 no.3
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    • pp.30-41
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    • 2019
  • Objectives Development of objective clinical measure for analyzing pediatric weakness has been studied. However, there is no gold standard clinical measures with acceptable validity and reliability were not provided yet and these has been major issue for clinics. Methods Some Korean medicine hospital outpatients (n=324) were recruited as participants, and 55 preliminary questions were given. Pediatric Weakness Scale (PWS) with five subscales and thirty questions were developed using factor analysis and item analysis. The internal consistency of PWS subscales were examined with using Cronbach's alpha. The correlations between PWS subscales and physical characteristics of Body Mass Index (BMI) and Ponderal Index (PI) were attested using Pearson's correlation. The differences between PWS subscale scores and profiles among 3 to 13 years old children were examined using profile analysis and ANOVA by gender. Results PWS five subscales explained 49.1% of total variance, and the range of Cronbach's alpha was from 0.700 to 0.803. The range of correlation coefficient between PWS total score and five subscales was from 0.643 to 0.748, and the PWS total score was significantly (p<0.001) correlated positively with BMI (r=-0.237) and negatively with PI (r=-0.280). The scores and profiles of PWS five subscales, BMI and PI were found to be significantly different among the all age groups. Conclusions Objective and validated clinical measure for analyzing pediatric weakness with five subscales was developed in current study, and foundations for screening, managing and treating pediatric weakness during the development were established as well. This study would contribute to the integrative education and clinical practice of the Eastern and Western medicine.

Application and Comparative Analysis of River Discharge Estimation Methods Using Surface Velocity (표면유속을 이용한 하천 유량산정방법의 적용 및 비교 분석)

  • Jae Hyun, Song;Seok Geun Park;Chi Young Kim;Hung Soo Kim
    • Journal of Korean Society of Disaster and Security
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    • v.16 no.2
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    • pp.15-32
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    • 2023
  • There are some difficulties such as safety problem and need of manpower in measuring discharge by submerging the instruments because of many floating debris and very fast flow in the river during the flood season. As an alternative, microwave water surface current meters have been increasingly used these days, which are easy to measure the discharge in the field without contacting the water surface directly. But it is also hard to apply the method in the sudden and rapidly changing field conditions. Therefore, the estimation of the discharge using the surface velocity in flood conditions requires a theoretical and economical approach. In this study, the measurements from microwave water surface current meter and rating curve were collected and then analyzed by the discharge estimation method using the surface velocity. Generally, the measured and converted discharge are analyzed to be similar in all methods at a hydraulic radius of 3 m or over or a mean velocity of 2 ㎧ or more. Besides, the study computed the discharge by the index velocity method and the velocity profile method with the maximum surface velocity in the section where the maximum velocity occurs at the high water level range of the rating curve among the target locations. As a result, the mean relative error with the converted discharge was within 10%. That is, in flood season, the discharge estimation method using one maximum surface velocity measurement, index velocity method, and velocity profile method can be applied to develop high-level extrapolation, therefore, it is judged that the reliability for the range of extrapolation estimation could be improved. Therefore, the discharge estimation method using the surface velocity is expected to become a fast and efficient discharge measurement method during the flood season.