신뢰도 예측 기반 신뢰도 성장 관리 : 감시체계 사례

김상부,박우재,유재우,이자경,용화영 한국품질경영학회 2019 품질경영학회지 Vol.47 No.1

Purpose: In this study, a reliability prediction based reliability growth management is suggested especially for the early development phase of a system and the case study of surveillance system is given. Methods: The proposed reliability prediction based reliability growth management procedures consists of 7 Steps. In Step 1, the stages for reliability growth management are classified according to the major design changes. From Step 2 to Step 5, system reliability is predicted based on reliability structures and the predicted reliabilities of subsystems (Level 2) and modules (Level 3). At each stage, by comparing the predicted system reliability with that of the previous stage, the reliability growth of the system is checked in Step 6. In Step 7, when the predicted value of sustem reliability does not satisfy the reliability goal, some design alternatives are considered and suggested to improve the system reliability. Results: The proposed reliability prediction based reliability growth management can be an efficient alternative for managing reliability growth of a system in its early development phase. The case study shows that it is applicable to weapon system such as a surveillance system. Conclusion: In this study, the procedures for a reliability prediction based reliability growth management are proposed to satisfy the reliability goal of the system efficiently. And it is expected that the use of the proposed procedures would reduce, in the test and evaluation phase, the number of corrective actions and its cost as well.

기동장비 신뢰도 성장 관리 연구 : 발사대 체계 사례

이용준 ( Lee Yj ),배공명 ( Bae Gb ),허영무 ( Heo Ym ),서재현 ( Seo Jh ),김상부 ( Kim Sb ),최재경 ( Choi Jk ),박우재 ( Park Wj ) 한국품질경영학회 2017 품질경영학회지 Vol.45 No.4

Purpose: In this study, the reliability growth management procedures for armed vehicle is suggested and an illustrative case study of launcher system is given. Methods: Crow-AMSAA model is adopted to manage reliability growth of armed vehicle using failure data acquired from development test phase to field operation phase. Between the development test phase and the production phase, the suggested reliability growth procedures for armed vehicle entails accelerated life test of the selected module whose design is changed to improve its reliability for assuring the target system reliability. And it can be verified through estimating the system reliability based on the failure data of field operation phase. Results: It is shown that the proposed reliability growth management procedures are effective for armed vehicle based on the case study of launcher system. After estimating the reliability of launcher system at every development test, some items are selected to change their designs for improving reliability. Accelerated life test is performed to prove the reliability improvement and finally it is verified through the field operation. Conclusion: The reliability growth management procedures for armed vehicle is suggested and the case study of launcher system shows it can be effective for managing the reliability growth of the armed vehicle.

Reliability growth analysis of <i>k-out-of-N</i> systems using matrix-based system reliability method

Byun, Ji-Eun,Noh, Hee-Min,Song, Junho Elsevier 2017 Reliability engineering & system safety Vol.165 No.-

<P><B>Abstract</B></P> <P>The advent of ever more complex systems in extensive areas of industries hampers efficient and accurate analysis of reliability and effective reliability-based decision making. Such difficulties may arise from the intricate formulation of system failure events, statistical dependence between component failure events, and the convoluted quantification of underlying probabilities of basic events. So-called <I>k-out-of-N</I> systems, which survive or succeed when at least <I>k</I> components are available among the total of <I>N</I> components, give rise to a high level of complexity. This type of systems are commonly introduced to secure a proper level of redundancy in operating engineering systems, but the intricate definition of the system events may elude the system reliability analysis. It is noted that such <I>k-out-of-N</I> systems are often tested and corrected over a certain period of time before their official usage or release in order to assure the target reliability of the system. For the purpose of reliability prognosis based on the data collected from the test period, reliability growth models (RGMs) have been widely used in software and hardware engineering. However, RGMs have been applied mostly to individual components, not at the system level. Furthermore, in complex systems such as <I>k-out-of-N</I> system, it is challenging to relate the reliability growth of components with that of the system. To address this need, in this paper, the matrix-based system reliability (MSR) method is extended to <I>k-out-of-N</I> systems by modifying the formulations of event and probability vectors. The proposed methods can incorporate statistical dependence between component failures for both homogeneous and non-homogeneous <I>k-out-of-N</I> systems, and can compute measures related to parameter sensitivity and relative importance of components. The reliability growths of components represented by RGMs are incorporated into the proposed system reliability method, so that the trend of <I>system</I> reliability growth can be effortlessly evaluated and predicted. Two numerical examples are introduced in this paper to demonstrate the proposed method and its applications: (1) hypothetical systems each consisting of series, parallel and <I>k-out-of-N</I> subsystems, and (2) a simplified high speed train system modeled by multiple <I>k-out-of-N</I> subsystems. Two types of RGMs, i.e. non-homogeneous Poisson process (NHPP) and Duane models are employed in these examples.</P> <P><B>Highlights</B></P> <P> <UL> <LI> MSR method is extended to evaluate the reliability growth of <I>k-out-of-N</I> systems. </LI> <LI> The time-varying reliability of system can be evaluated from that of components. </LI> <LI> The extended MSR method can account for statistical dependence between components. </LI> <LI> By-products of reliability analysis can support systematic decision-making. </LI> <LI> Numerical examples show the MSR method is applicable to various configurations. </LI> </UL> </P>

STUDY OF RCM-BASED MAINTENANCE PLANNING FOR COMPLEX STRUCTURES USING SOFT COMPUTING TECHNIQUE

손영탁,김배영,박기준,이호용,서명원,김현준 한국자동차공학회 2009 International journal of automotive technology Vol.10 No.5

To guarantee the efficiency of maintenance strategies for a complex structure, safety and cost limitations must be considered. This research introduces RCM-based (Reliability Centered Maintenance) life cycle optimization for reasonable maintenance. The design variable is the reliability of each part, which consists of a complex structure, while the objective is to minimize the total cost function in order to maintain the system within the desired system reliability. This research constructs the cost function that can reflect the current operating condition and maintenance characteristics of individual parts by generating essential cost factors. To identify the optimal reliability of each component in a system, this paper uses a Neuro-Evolutionary technique. Additionally, this research analyzes the reliability growth of a system by using the AMSAA (Army Material Systems Analysis Activity) model to estimate the failure rate of each part. The MTBF (Mean Time Between Failure) and the failure rate of the whole system, which is responding to the individual parts, are estimated based on the history data by using neural networks. Finally, this paper presents the optimal life cycle of a complex structure by applying the optimal reliability and the estimated MTBF to the RAMS (Reliability, Availability, Maintainability, and Safety) algorithm. To guarantee the efficiency of maintenance strategies for a complex structure, safety and cost limitations must be considered. This research introduces RCM-based (Reliability Centered Maintenance) life cycle optimization for reasonable maintenance. The design variable is the reliability of each part, which consists of a complex structure, while the objective is to minimize the total cost function in order to maintain the system within the desired system reliability. This research constructs the cost function that can reflect the current operating condition and maintenance characteristics of individual parts by generating essential cost factors. To identify the optimal reliability of each component in a system, this paper uses a Neuro-Evolutionary technique. Additionally, this research analyzes the reliability growth of a system by using the AMSAA (Army Material Systems Analysis Activity) model to estimate the failure rate of each part. The MTBF (Mean Time Between Failure) and the failure rate of the whole system, which is responding to the individual parts, are estimated based on the history data by using neural networks. Finally, this paper presents the optimal life cycle of a complex structure by applying the optimal reliability and the estimated MTBF to the RAMS (Reliability, Availability, Maintainability, and Safety) algorithm.

신뢰성 성장 기반의 유도무기 시험평가 방안 연구

김두현,김상훈 한국방위산업학회 2014 韓國防衛産業學會誌 Vol.21 No.3

본 연구는 연구개발단계에서 유도무기 시험평가를 신뢰성 성장 관리를 통해 수행 가능성을 연구한 것이다. One-Shot 체계인 유도무기가 개발자․제작자에 의해 생산․배치된 후 사용자인 군의 초기 운용과정에서 불명중되면 시험평가 방법의 적절성에 논란이 제기된다. 이에 따라 현재의 명중률 중심 시험평가를 보다 합리적으로 개선하기 위해 신뢰성 성장(Reliability Growth) 관점에서 수행하는 방안으로의 적용 가능성을 사례 분석을 통해 제안하였다. 신뢰성 성장 분석을 위해 현재 미육군에서 사용하고 있는 RGA(Reliability Growth & Repairable System Data Analysis) 프로그램을 사용하였다. 향후에는 적용 가능성 연구결과를 기반으로 유도무기 시험평가시 신뢰성 성장 관리모델 및 절차를 제시하고자 한다. This study is on the method of the guided missile test and evaluation based on the Reliability Growth Management in the research and development stage. The Guided Missile One-shot System is often the subject of disputes on the appropriateness of its test and evaluation process when misfiring occurs in the initial operation phase. In this paper, the Reliability Growth method is presented for the improvement of the guided missile test, instead of the Hit-Probability-oriented test. Though the results of the Development Test (DT) and the Operational Test (OT) of the guided missile have been accepted based on the hit probability test criteria, this paper analyzes the proper performance of the objective reliability analysis from the viewpoint of reliability. For the reliability tracking and projection, this paper analyzes the data with the Reliability Growth & Repairable System Data Analysis (RGA) software, which is being used for the Army Materials System Activity (AMSAA) of the US army. Finally, the guided missile test method was proposed according to the reliability growth management, and the additional study was presented.

성장-변형률법을 이용한 신뢰성 기반 형상 최적화

오영규(Young-kyu Oh),박재용(Jae-yong Park),임민규(Min-gyu Im),박재용(Jae-yong Park),한석영(Seog-young Han) 한국생산제조학회 2010 한국생산제조학회지 Vol.19 No.5

This paper presents a reliability-based shape optimization (RBSO) using the growth-strain method. An actual design involves uncertain conditions such as material property, operational load, Poisson’s ratio and dimensional variation. The purpose of the RBSO is to consider the variations of probabilistic constraint and performances caused by uncertainties. In this study, the growth-strain method was applied to shape optimization of reliability analysis. Even though many papers for reliability-based shape optimization in mathematical programming method and ESO (Evolutionary Structural Optimization) were published, the paper for the reliability-based shape optimization using the growth-strain method has not been applied yet. Growth-strain method is applied to performance measure approach (PMA), which has probabilistic constraints that are formulated in terms of the reliability index, is adopted to evaluate the probabilistic constraints in the change of average mises stress. Numerical examples are presented to compare the DO with the RBSO. The results of design example show that the RBSO model is more reliable than deterministic optimization. It was verified that the reliability-based shape optimization using growth-strain method are very effective for general structure. The purpose of this study is to improve structure’s safety considering probabilistic variable

AMSAA 모델을 이용한 일회성 체계의 신뢰도성장 예측

김명수(Myung Soo Kim),정재우(Jae Woo Chung),이종신(Jong Sin Lee) 한국신뢰성학회 2014 신뢰성응용연구 Vol.14 No.4

A one-shot device is defined as a product, system, weapon, or equipment that can be used only once. After use, the device is destroyed or must undergo extensive rebuild. Determining the reliability of a one-shot device poses a unique challenge to the manufacturers and users due to the destructive nature and costs of the testing. This paper presents a reliability growth prediction for a one-shot system. It is assumed that 1) test duration is discrete(i.e. trials or rounds); 2) trials are statistically independent; 3) the number of failures for a given system configuration is distributed according to a binomial distribution; and 4) the cumulative expected number of failures through any sequence of configurations is given by AMSAA model. When the system development is represented by three configurations and the number of trials and failures during configurations are given, the AMSAA model parameters and reliability at configuration 3 are estimated by using a reliability growth analysis software. Further, if the reliability growth predictions do not meet the target reliability, the sample size of an additional test is determined for achieving the target reliability.

Selection of a Predictive Coverage Growth Function

Park, Joong-Yang,Lee, Gye-Min The Korean Statistical Society 2010 Communications for statistical applications and me Vol.17 No.6

A trend in software reliability engineering is to take into account the coverage growth behavior during testing. A coverage growth function that represents the coverage growth behavior is an essential factor in software reliability models. When multiple competitive coverage growth functions are available, there is a need for a criterion to select the best coverage growth functions. This paper proposes a selection criterion based on the prediction error. The conditional coverage growth function is introduced for predicting future coverage growth. Then the sum of the squares of the prediction error is defined and used for selecting the best coverage growth function.

소프트웨어 신뢰성 모델링 기반 소프트웨어 품질 측정

정혜정 한국융합학회 2019 한국융합학회논문지 Vol.10 No.4

This study proposes a method to measure software reliability according to software reliability measurement model to measure software reliability. The model presented in this study uses the distribution of Non - Homogeneous Poisson Process and presents a measure of the software reliability of the presented model. As a method to select a suitable software reliability growth model according to the presented model, we have studied a method of proposing an appropriate software reliability function by calculating the mean square error according to the estimated value of the reliability function according to the software failure data. In this study, we propose a reliability function to measure the software quality and suggest a method to select the software reliability function from the viewpoint of minimizing the error of the estimation value by applying the failure data. 본 연구는 소프트웨어 신뢰성을 측정하기 위해 소프트웨어 신뢰도 측정 모형에 따라 소프트웨어 신뢰도를 측정하는 방법을 제시하려 한다. 본 연구에서 제시한 모형의 형태는 비동질적 포아송 과장의 분포를 이용하였으며, 제시된 모형의 소프트웨어 신뢰도를 측정하는 방안을 제시하였다. 제시된 모형에 따라서 적합한 소프트웨어 신뢰도 성장 모형을 선택하는 방법으로는 소프트웨어 고장 데이터에 따라서 신뢰도 함수의 추정 값에 따른 평균제곱오차를 계산하여 적합한 소프트웨어 신뢰도 함수를 제안하는 방법을 연구하였다. 본 연구에서는 소프트웨어 품질을 측정하기 위한 신뢰도 함수를 제안하기 위하여 모델을 제시하고 고장데이터를 적용하여 추정 값의 오차를 최소화하는 관점에서 소프트웨어 신뢰도 함수를 선택할 수 있는 방안을 제시한 연구로 판단된다.

한국형 고무차륜경량전철시스템(K-AGT) 신뢰성평가 연구

이호용(Ho-Yong Lee),이안호(An-Ho Lee),조홍식(Hong-Shik Cho),홍재성(Jai-Sung Hong),한석윤(Seok-Youn Han) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.11

Korea Railroad Research Institute(KRRI) developed the Driverless Rubber Tired Korea-AGT (Model: K-AGT) from 1999 to 2004. We have finished the safety and performance tests of K-AGT, but the reliability test result was not effective level. In the paper, analyzed whether can improve in this research through authoritativeness growth analysis to get satisfied result. Data obtained from this testing can be used to evaluate the growth of reliability. The most widely used traditional growth tracking model5 is included as IEC International standard. In this paper, we demonstrated reliability analysis using growth model of driverless rubber tired K-AGT system to prove reliability of development system. Therefore, we introduce the well-known NHPP model and analyze a reliability growth using ReliaSoft's RGA software.