第二回研究会(通算第二十回)

広島大学の土肥先生のお世話で下記の講演会を開催致します.ご参加よろしくお願い致します.

日時:平成29年6月6日(火) 14:30-15:30
場所:広島大学工学部 A1-731
講師:Ming J Zuo, Professor, University of Alberta, Canada
講演題目:Reliability Assurance and PHM: Key Challenges
講演概要:This talk addresses key challenges in assurance of the reliability of systems in continuous operation utilizing condition monitoring data. Key issues include quantification of the health status of system in operation and the relationship between health indicators and the predicted remaining useful life. The covered research aspects include fault detection, fault assessment, fault diagnosis, deterioration trend prediction, reliability assessment, maintenance optimization models and methods, and decision-making tools for inspection, maintenance, and operation.

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第三回研究会(通算第二十一回)

国際会議(MMR2017)におけるシステム信頼性研究部会によるスペシャルセッション

日時(会期):2017年7月3日~6日
場所:INP-ENSE^3, GreEn-ER, 21 Avenue des martyrs, 38000 Grenoble, France
Web site: http://mmr2017.imag.fr/

本年開催のMMR (Mathematical Methods in Reliability) にSpecial Sessionを3件設定させて頂き,それぞれ3件ずつ,日本からの参加予定者の方々にご講演・討論をお願いしております.ご興味のお有りの方は是非この機会にグルノーブルへお出かけください.現地にてお待ちしております.

Advanced Mathematical Methods in System Reliability and Maintenance – Special session organized by the Operations Research Society of Japan (ORSJ) – 1

Presenter 1: Taishin Nakamura (Tokyo Metropolitan University)
Title: Necessary Conditions for Optimal Arrangement of Connected-(r,s)-out-of-(m,n):F Lattice System with Minimal Cuts Overlapping
Authors: Taishin Nakamura, Hisashi Yamamoto, Xiao Xiao, Natsumi Takahashi and Tomoaki Akiba
Abstract: A connected-(r,s)-out-of-(m,n):F lattice system consists of m×n components arranged as an (m,n) matrix, and fails if and only if the system has an (r,s) sub-matrix where all components fail. One of the most significant problems in reliability theory is the component arrangement problem (CAP) on the assumption that component reliabilities are given and components are interchangeable. The CAP is to find optimal arrangements of components to maximize the system reliability. By taking optimal arrangements into account, we can make the best use of limited resources and maximize the performance of the system.
In this study, we provide necessary conditions for the optimal arrangement of the connected-(r,s)-out-of-(m,n):F lattice system with its minimal cuts overlapping, that is, m<2r or n<2s. Since we calculate the reliability of only the systems corresponding to the arrangements satisfying the conditions, we can considerably reduce the search space for the CAP. We evaluate the performance of the proposed algorithm by performing numerical experiments.

Presenter 2: Lu Jin (The University of Electro-Communications)
Title: Operation and Maintenance Policy with Flexible Load Sharing
Authors: Lu Jin, Tomofumi Uwano, and Kazuyuki Suzuki
Abstract: An integrated operation and maintenance policy with flexible load sharing is proposed for multiple-component deteriorating systems under a constant total workload. The underlying deterioration process of the system, which depends on the workload allocation, is described by a discrete-time Markov chain. The decision-making problem is formulated as a Markov decision process that minimizes the total expected cost (both operation and maintenance costs) on an infinite horizon. The properties of the resulting optimal decision policies are investigated, and a set of sufficient conditions for a monotone policy to be optimal are provided. The efficiency of the proposed integrated operation and maintenance policy with flexible load sharing is demonstrated through a numerical example.

Presenter 3: Hiroyuki Okamura (Hiroshima University)
Title: A note on computation of quasi-stationary distribution in continuous-time Markov chains
Authors: Hiroyuki Okamura and Tadashi Dohi
Abstract: This paper discusses the computation of quasi-stationary distribution for continuous-time Markov chain (CTMC). The quasi-stationary distribution is defined as a left eigenvector of an infinitesimal generator of the CTMC with absorbing states. Compared to the computation of steady-state probability vector of CTMC, the computation cost of quasi-stationary distribution is much higher. In the paper, we introduce an iterative approach to obtain the quasi-stationary distribution, which is similar to Gauss-Seidel algorithm for the computation of steady-state probability vector.

System Reliability and Maintenance Modeling – Special session organized by the Operations Research Society of Japan (ORSJ) – 2

Presenter 1: Shuhei Ota (Hosei University)
Title: A study on reliability deterioration and improvement of coherent
systems under dependent failure-occurrence environment
Authors: Shuhei Ota and Mitsuhiro Kimura
Abstract: In this study, we investigate the effect of dependent failure
occurrence on system reliability assessment. In general, it is known
that an n-component parallel system cannot deliver its designed
reliability if the lifetimes of the individual components have positive
dependence. On the other hand, an $n$-component series system can exceed
its designed reliability under such dependent failure-occurrence
environment. This research analyzes to what extent the dependence among
the components worsens/improves the reliability of n-component coherent
systems. The dependence among the components is modeled by FGM copula.
We obtain the results by using numerical examples. Moreover, in these
examples, we newly consider the allowable values of the parameters of
FGM copula although they have been simply assumed [0,1]^n in the
literature.

Presenter 2: Syouji Nakamura (Kinjo Gakuin University)
Title: Optimum Incremental Backup Policies with Failures at Random
Updating Times
Authors: Syouji Nakamura, Xufeng Zhao, and Toshio Nakagawa
Abstract: In order to ensure the data security, plans of incremental
backups are usually set up to save the costs which is suffered from full
backups. In this paper, we suppose that failures occur at data updating
times and incremental backups are implemented only at the end of data
updates and full backups are done at time $T$ and update $N$ to balance
the costs of data backup and failure recovery. Using the theory of
renewal process, we obtain the expected costs of backup and recovery and
the expected cost rates for full backups. Optimum solutions of $T$ and $
N$ to minimize the expected cost rates are discussed in analytical ways
and computed with numerical examples.

Presenter 3: Shinji Inoue (Kansai University)
Title: Markovian Imperfect Debugging Modeling for Software Reliability
Assessment with Change-Point
Authors: Shinji Inoue and Shigeru Yamada
Abstract: We discuss Markovian software reliability modeling with the
effects of change-point and imperfect debugging environment. Testing-
time when the characteristic of the software failure-occurrence or fault
-detection phenomenon changes notably is called {¥it change-point}.
Considering the effect at change-point on software reliability growth
process must be important to improve the accuracy of software
reliability assessment. And, assuming imperfect debugging activities in
software reliability modeling contributes to reflecting more actual
situation of debugging activities. We also show numerical illustration
of our model for software reliability analysis by using actual data.

Warranty and Maintenance Modeling with Applications – Special session organized by the Operations Research Society of Japan (ORSJ) – 3

Presenter 1: Tomohiro Kitagawa (National Defence Academy of Japan)
Title: Three repair options depending on failure time for a system equipped on ship
Authors: Tomohiro Kitagawa, Tetsushi Yuge, and Shigeru Yanagi
Abstract: A maintenance model for a system equipped on ship taking a voyage with a random duration is proposed. When a failure occurs, one action is chosen from three, return to the base, instantaneous repair on-site and to leave it alone and repair it after the end of the voyage. Our goal is to determine the optimal action depending on the occurrence time of failures, where the optimal policy minimizes the expected cost until the completion of one voyage, ensuring a certain mean availability.

Presenter 2: Nobuyuki Tamura (Hosei University)
Title: State-age-dependent replacement policy for a semi-Markovian deteriorating system with major and minor failures
Author: Nobuyuki Tamura
Abstract: We consider a multi-state system whose deterioration is modeled as a semi-Markov process with an absorbing state. The system can suffer major and minor failures. When the system reaches the absorbing state, a major failure occurs and the system is replaced. Meanwhile, minor failures can occur depending upon the state and the sojourn time. Upon the occurrence of a minor failure, the system is minimally repaired. For the system, we propose a state-age-dependent replacement policy which minimizes the expected long-run cost rate. Also, we investigate structural properties of the optimal replacement policy.

Presenter 3: Yu Hayakawa (Waseda University)
Title: Delayed reporting of faults in warranty claims
Authors: Richard Arnold, Stefanka Chukova, and Yu Hayakawa
Abstract: We present a model for the delayed reporting of faults: multiple non-fatal faults are accumulated and then simultaneously reported and repaired. The reporting process is modelled as a stochastic process dependent on the underlying stochastic process generating the faults. The joint distribution of the reporting times and numbers of reported faults is derived. We will also present a few extensions of the above model, which deal with multiple fault types, planned preventative maintenance and customer rush.

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第一回研究会(通算第十九回)

日本信頼性学会 春季シンポジウムにおける
システム信頼性研究部会オーガナイズドセッション

日時:2017年5月31日(水)13:00から(開催プログラムはこちら
場所:一般財団法人 日本科学技術連盟 本部(西新宿2-7-1小田急第一生命ビル

第一回研究会では,日本信頼性学会主催の春季シンポジウムにて,オーガナイズドセッションを企画し,以下の4件の講演を予定しております.みなさまのご参加をお待ちしております.春季シンポジウムへの参加登録方法などはこちらをご覧ください(リンク

(1)
Title: A note on a statistical detection method of cascading failure for parallel systems
Authors: Shuhei OTA and Mitsuhiro KIMURA (Hosei University)
Abstract: Cascading failure, one kind of dependent failures, is a phenomenon in which the failure occurrence of one component triggers other failures. The trigger component can cause a huge number of failures after it fails if other components strongly rely on the trigger component. For example, this phenomenon is observed in complex network systems such as blackouts of power transmission systems. As a result, the cascading failure causes the reliability deterioration of the systems. From the viewpoint of reliability management, the factors of the cascading failure should be ideally eliminated before the utilization of the system. In this study, we propose a statistical detection method of the cascading failure occurrence in n-component parallel systems. This research contributes to the cause analysis of the cascading failure occurrence in the n-component parallel system. The cascading failure is modeled by hazard rate switching mechanism. We assume that the lifetime distribution of the remaining components changes if such a trigger component actually exists and fails. The cascading failure occurrence can be detected by identifying the change of the distribution. The performance of the proposed method is demonstrated by simulation studies.

(2)
Title: Conditions for the optimal arrangement of a connected-(m-1,s)-out-of-(m,n):F lattice system
Authors: Taishin NAKAMURA, Hisashi YAMAMOTO, Sayaka MATSUO, Xiao XIAO (Tokyo Metropolitan University), and Tomoaki AKIBA (Chiba Institute of Technology)
Abstract: A connected-(r,s)-out-of-(m,n):F lattice system consists of m×n components arranged as an (m,n) matrix, and fails if and only if the system has an (r,s) sub-matrix where all components are failed. One of the most important problems in reliability theory is the component arrangement problem (CAP) on the assumption that component reliabilities are given, and components are interchangeable. The CAP is to find the optimal arrangement of components to maximize system reliability. By taking CAP into account, we can make the best use of limited resources and maximize the performance of the system.
In this study, we provide necessary conditions for the optimal arrangement of the connected-(r,s)-out-of-(m,n):F lattice system in the case of r=m-1. Since we only need to calculate the reliability of the systems corresponding to the arrangements satisfying the necessary conditions, our proposal necessary conditions can considerably reduce the search space for the patterns of component arrangements. We evaluate the performance of the proposed algorithm by numerical experiments.

(3)
Title: Compromised life test plan for accelerated degradation test of three factor stress level
Author: Takenori SAKUMURA (Chuo University)
Abstract: Accelerated degradation tests (ADT) are often used to quickly find the life of materials such as electrical insulators. An ADT consists of several high levels of stress and the number of samples at that level. Each sample is subjected to the stress for a certain evaluation time and the degradation rate at that time is measured. The time when the degradation reaches a certain threshold is regarded as the failure time. The lifetime can be predicted from the obtained failure time data under the assumption that the physical law is empirically established between the stress and the lifetime and the logarithmic lifetime follows a specific probability distribution under a certain stress. In this research, focusing on finding the optimum sample allocation number, consider the case where the number of stress levels is three. In order to consider the reality, we use the mathematical model obtained from actual experimental data and its parameter value.

(4)
Title: Analysis for the Conditions of Component Assignment for the Optimal Arrangement of a k-Window System
Author: Tomoaki Akiba (Chiba Institute of Technology)
Abstract: k-window system in this study is an application system of the consecutive-k-out-of-n:F system. This system can be expressed to the occurring of a failure in the system when a certain extent intensive components failure happens in the system. One of the most important problems for this kind of system is the optimal arrangement problem. In the previous study, we confirmed by the simulation approaches that optimal arrangement of k-window system. However, this component arrangement depends on the system parameters k, r and components reliabilities. In this study, we provide necessary conditions of component assignment for the optimal arrangement of k-window system by the mathematical analysis.

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第十八回信頼性研究会

日時:2016年12月17日(土) 10:00~12:00
場所:マホロバマインズ三浦(神奈川県三浦市南下浦町上宮田3231)
ホテルのwebサイトはこちら

2016年度最後のOR学会信頼性研究会は, 上記の通り神奈川県三浦市で開催する予定です. 前日の16日(金)には電子情報通信学会信頼性研究会が同じ場所で開催されますので(発表申込:10月17日), 併せてご案内申し上げます.

講師と題目
(1)
講師:北川智大 氏(防衛大学校)
題目:ランダム作業時間に従事する船舶搭載システムの保全方策について
概要:船舶がある確率分布に従うランダムな長さの航海に従事する場合,それに搭載されているシステムについても同じ時間だけ作業することが求められる.このような船舶搭載システムの保全は,一般的に航海終了後に岸壁やドックで行われるため,修理等の遅れ時間を加味する必要がある.本発表は2部構成となっており,第1部では,システムの故障が船内の予備アイテム等により即座に修理可能な場合と,航海終了後に修理される場合とに確率的に区別できる問題を扱う.この確率が予備アイテム等の搭載コストと既知の関係があると仮定し,ある平均アベイラビリティを満たしつつ,平均コストレートを最小にする最適な確率について議論する.これは,船舶に搭載する予備アイテム等にかけるコストを最適化することと同等である.第2部では,ランダムな長さの航海時間が事前に付与される状況を想定する.システムの故障に対して,航海中に緊急的に修理するか,航海終了後に修理するか選択できるとし,故障発生時刻に応じた合理的な修理時期の選択ついて議論する.

(2)
講師:太田修平 氏(法政大学大学院)
題目:依存故障するn素子直並列システムの信頼性解析~EFGMコピュラを用いて~
概要:互いに依存して故障する素子によって構成される,コヒーレントなシステムの故障の特性を解析することは,信頼性工学において,非常に重要な課題である.本講演では,複数素子の寿命時間が互いに確率的に依存している,n素子直並列システムの信頼性解析について議論する.具体的には,n素子直並列システムを,同時分布関数のEFGMコピュラによる表現を用いてモデル化し,そのシステムの信頼性評価を行う.特に,n変量EFGMコピュラがもつ,依存パラメータの制約に注意しながら,システムのMTTFを解析的に導出し,システムの寿命と,素子間の依存性の強さの関係について議論する.また,いくつかの数値例とともに,モデルの特性について述べる.

(3)
講師:Wong Young Yun 氏(Pusan National University, Korea)
題目:How to determine maintenance units in modularized systems?
概要:In this paper, we consider an optimization problem in which we determine the maintenance units in modularized systems. The modularized system has a hierarchical structure in design phase and has several modules. Each module also consists of some components. When some components fail, then the system fails and we should maintain correctively the system. We can replace the failed components or the module with the failed components. We want to determine the maintenance units in the modularized system with hierarchical structure. The system availability and maintenance cost are used as optimization criteria. Numerical examples are also studied.

懇親会(研究部会忘年会):研究会終了後, 横須賀市内で開催を予定しています.

【注意】研究会への参加費は無料ですが,資料等の準備の関係上,聴講を希望する方は 12月9日(金)までに幹事までお知らせください.

問合せ先 法政大学 田村信幸 E-mail: sigrelwebmaster@gmail.com
信頼性研究部会HP(10月までの情報はこちら

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第十七回信頼性研究会

日時:2016年10月15日(土) 12:00~19:00 (情報交換会: 17:15~19:00)
場所:常翔学園大阪センター
大阪市北区梅田3-4-5 毎日インテシオ3F
(研究会場:301+302セミナー室、情報交換会場:ラウンジ翔)

本会は以下4研究部会合同での開催となりました.

主催:
「確率モデルとその応用」研究部会
「信頼性」研究部会
「待ち行列」研究部会
「不確実性環境下の意思決定モデリング」研究部会

当信頼性研究部会からは,以下の講演者を推薦し,ご登壇頂きました.

講演者: 早川 有(早稲田大学)
講演題目: Delayed reporting of faults in warranty claims
共同研究者: Richard Arnold, Stefanka Chukova and Yu Hayakawa
講演概要: When a complex system is operated, it may experience multiple faults. If the system is operating under warranty these faults may be claimed for and repaired at zero or minimal cost to the consumer. However if the faults do not lead to system failure the user may find it inconvenient to claim for each repair as it occurs, and may instead delay making a report or claim until a sufficiently large number of faults has accumulated. In this talk, the speaker presented a model for the delayed reporting of faults: multiple non-fatal faults are accumulated and then simultaneously reported and repaired. The reporting process is modelled as a stochastic process dependent on the underlying stochastic process generating the faults. The joint distribution of the reporting times and numbers of reported faults is derived.

その他,詳細はリンク先をご覧ください(リンク

カテゴリー: ご案内