Search results
1 – 10 of 33Tetsushi Yuge, Shinya Ozeki and Shigeru Yanagi
This paper aims to present two methods for calculating the steady state probability of a repairable fault tree with priority AND gates and repeated basic events when the minimal…
Abstract
Purpose
This paper aims to present two methods for calculating the steady state probability of a repairable fault tree with priority AND gates and repeated basic events when the minimal cut sets are given.
Design/methodology/approach
The authors consider a situation that the occurrence of an operational demand and its disappearance occur alternately. We assume that both the occurrence and the restoration of the basic event are statistically independent and exponentially distributed. Here, restoration means the disappearance of the occurring event as a result of a restoration action. First, we obtain the steady state probability of an output event of a single‐priority AND gate by Markov analysis. Then, we propose two methods of obtaining the top event probability based on an Inclusion‐Exclusion method and by considering the sum of disjoint probabilities.
Findings
The closed form expression of steady state probability of a priority AND gate is derived. The proposed methods for obtaining the top event probability are compared numerically with conventional Markov analysis and Monte Carlo simulation to verify the effectiveness. The result shows the effectiveness of the authors’ methods.
Originality/value
The methodology presented shows a new solution for calculating the top event probability of repairable dynamic fault trees.
Details
Keywords
Julie Morin, Benjamin De Coster, Raphaël Paris, François Flohic, Damien Le Floch and Franck Lavigne
Following the 26 December 2004 tsunami, Planet Risk NGO took part in the international research program TSUNARISK and ATIP‐CNRS Jeune Chercheur. The aim of this paper is to…
Abstract
Purpose
Following the 26 December 2004 tsunami, Planet Risk NGO took part in the international research program TSUNARISK and ATIP‐CNRS Jeune Chercheur. The aim of this paper is to encourage the development of tsunami‐resilient communities essentially through educative actions.
Design/methodology/approach
The tsunami risk in Indonesia was assessed by researchers. Planet Risk then used scientific findings and advice for building adapted prevention actions among Javanese populations.
Findings
Many people could have survived if they had received a basic knowledge of tsunamis. The Indonesian public as well as local authorities must be educated to face tsunami risk. To be efficient, this education must be adapted to local cultural and geographical characteristics. Collaboration between researchers and practitioners is a good means of reaching such an objective.
Originality/value
The paper is the result of a two‐year successful collaboration between interdisciplinary scientific teams and an NGO team. It demonstrates that an efficient prevention scheme can be implemented through this kind of collaboration. To the authors' knowledge it is the first time that such tsunami education programmes have been led in Indonesia.
Details
Keywords
Tetsushi Yuge, Taijiro Yoneda, Nobuyuki Tamura and Shigeru Yanagi
This paper aims to present a method for calculating the top event probability of a fault tree with priority AND gates.
Abstract
Purpose
This paper aims to present a method for calculating the top event probability of a fault tree with priority AND gates.
Design/methodology/approach
The paper makes use of Merle's temporal operators for obtaining the minimal cut sequence set of a dynamic fault tree. Although Merle's expression is based on the occurrence time of an event sequence, the paper treats the expression as an event containing the order of events. This enables the authors to treat the minimal cut sequence set by using the static fault tree techniques. The proposed method is based on the sum of disjoint products. The method for a static FT is extended to a more applicable one that can deal with the order operators proposed by Merle et al.
Findings
First, an algorithm to obtain the minimal cut sequence set of dynamic fault trees is proposed. This algorithm enables the authors to analyze reasonably large scale dynamic fault trees. Second, the proposed method of obtaining the top event probability of a dynamic fault tree is efficient compared with an inclusion‐exclusion based method proposed by Merle et al. and a conventional Markov chain approach. Furthermore, the paper shows the top event probability is derived easily when all the basic events have exponential failure rates.
Originality/value
The methodology presented shows a new solution for calculating the top event probability of dynamic fault trees.
Details
Keywords
Arash Shahin, Ashraf Labib, Soroosh Emami and Mahdi Karbasian
Decision-Making Grid (DMG) is used for determining maintenance tactics and is associated with the reliability and risk management of assets. In this grid, decision making is…
Abstract
Purpose
Decision-Making Grid (DMG) is used for determining maintenance tactics and is associated with the reliability and risk management of assets. In this grid, decision making is performed based on two indicators of Mean Time to Repair (MTTR) and frequency of failures. The purpose of this paper is to improve DMG by recognizing interdependence among failures.
Design/methodology/approach
Fault Tree Analysis and Reliability Block Diagram have been applied for improving DMG. The proposed approach has been examined on eight equipment of the steel making and continuous casting plant of Mobarakeh Steel Company.
Findings
Findings indicate different positions of equipment in the cells of the new grid compared to the basic grid.
Research limitations/implications
DMG is limited to two criteria of frequency of failures and MTTR values. In both basic and new DMGs, cost analysis has not been performed. The application of the proposed approach will help the reliability/maintenance engineers/analysts/managers to allocate more suitable maintenance tactics to equipment. This, in turn, will enhance the equipment life cycle and availability as the main objectives of physical asset management.
Originality/value
A major limitation of basic DMG is that the determined tactic based on these two indicators might not be an appropriate solution in all conditions, particularly when failures are interdependent. This has been resolved in this paper.
Details
Keywords
Abstract
Purpose
Calculating the exact top event probability of fault trees is an important analysis in quantitative risk assessments. However, it is a difficult problem for the trees with complex structure. Therefore, the paper aims to provide an efficient calculation method to obtain an exact top event probability of a fault tree with many repeated events when the minimal cut sets of the tree model are given.
Design/methodology/approach
The method is based on the inclusion‐exclusion method. Generally, the inclusion‐exclusion method tends to get into computational difficulties for a large‐scale fault tree. The computation time has been reduced by enumerating only non‐canceling terms.
Findings
The method enables the calculation of the probability more quickly than the conventional method. The effect increases as the number of repeated events increases, namely the tree structure becomes complex. This method also can be applied to obtain the lower and upper bounds of the top event probability easily.
Originality/value
The paper expresses the top event probability by using only non‐canceling terms. This is the first application in fault tree analysis.
Details
Keywords
Emanuele Lettieri, Cristina Masella and Giovanni Radaelli
The paper aims to discuss a systematic review of the literature about disaster management within the period 1980‐2006.
Abstract
Purpose
The paper aims to discuss a systematic review of the literature about disaster management within the period 1980‐2006.
Design/methodology/approach
The research protocol is based on the methodology that is commonly used in healthcare for analysing the literature and provides a state‐of‐art medical discipline. The paper presents both a descriptive analysis and a thematic analysis in order to provide a state‐of‐art of international literature. The research protocol is provided in order to make transparent the review process.
Findings
The descriptive analysis highlights the peculiarities of the literature in terms of attention paid during the years, country of provenience and clusters of content of the selected papers. The thematic analysis deepens the content of the papers formalising the state of art.
Research limitations/implications
The review considered only academic journals and peer‐reviewed published papers, excluding working papers and books.
Practical implications
Through both the analyses the authors argue for scholars in disaster management specific streams for further research and for providing practitioners with a state of art of disaster management discipline.
Originality/value
The paper is original and is aimed at translating to the disaster management discipline the methodology of the systematic review commonly used in healthcare disciplines.
Details
Keywords
Xin Feng, Lei Yu, Weilong Tu and Guoqiang Chen
With the development of science and technology, more creators are trying to use new crafts to represent the cultural trends of the social media era, which makes cultural heritage…
Abstract
Purpose
With the development of science and technology, more creators are trying to use new crafts to represent the cultural trends of the social media era, which makes cultural heritage innovative and new genres emerge. This compels the academic community to examine craft from a new perspective. It is very helpful to understand the hidden representational structure of craft more deeply and improve the craft innovation system of cultural and creative products that we deconstruct the craft based on Complex Network and discover its intrinsic connections.
Design/methodology/approach
The research crawled and cleaned the craft information of the top 20% products on the Forbidden City’s cultural and creative products online and then performed Complex Network modeling, constructed three craft representation networks among function, material and technique, quantified and analyzed the inner connections and network structure of the craft elements, and then analyzed the cultural inheritance and innovation embedded in the craft representation networks.
Findings
The three dichotomous craft representation networks constructed by combining function, material and technique: (1) the network density is low and none of them has small-world characteristics, indicating that the innovative heritage of the craft elements in the Forbidden City’s cultural and creative products is at the stage of continuous exploration and development, and multiple coupling innovation is still insufficient; (2) all have scale-free characteristics and there is still a certain degree of community structure within each network, indicating that the coupling innovation of craft elements of the Forbidden City’s cultural and creative products is seriously uneven, with some specific “grammatical combinations” and an Island Effect in the network structure; (3) the craft elements with high network centrality emphasize the characteristics of decorative culture and design for the masses, as well as the pursuit of production efficiency and economic benefits, which represent the aesthetic purport of contemporary Chinese society and the ideological trend of production and life.
Originality/value
The Forbidden City’s cultural and creative products should continue to develop and enrich the multi-coupling innovation of craft elements, clarify and continue their own brand unique craft genes, and make full use of the network important nodes role.
Details
Keywords
Huda Khan, Nadia Zahoor, Ahmad Arslan and Zaheer Khan
This study aims to understand the dynamics underpinning the exit and re-entry strategies adopted by multinational enterprises (MNEs) in an emerging market, Pakistan.
Abstract
Purpose
This study aims to understand the dynamics underpinning the exit and re-entry strategies adopted by multinational enterprises (MNEs) in an emerging market, Pakistan.
Design/methodology/approach
This study undertook an in-depth historical case study of Yamaha Motorcycles, which had initially entered Pakistan as a joint venture but had then exited and re-entered as a wholly owned subsidiary.
Findings
This study found that, despite its status as a market leader and one of the older players in the Pakistani market, changing market dynamics in the 2000s – especially the increased competition brought by more affordable (inexpensive) Chinese motorcycles and the weak enforcement of industrial policies – had pushed Yamaha Motorcycles to exit. Another factor that had contributed to its exit were differences in risk perception and strategies with its local joint venture partner (a Pakistani business group). Hence, both firm-level and institutional factors had played significant roles in Yamaha’s market exit. This study further found that re-entering in a wholly owned subsidiary operation mode had been beneficial for the firm, as it gained a significant market share due to its focus on innovation and on capturing a market niche, which had earlier not been its main focus. The findings also suggest that opportunity logics and multiple forms of learning can be important for a firm’s re-entry into a host market – such as experiential (i.e. learning from experience) and vicarious learning (i.e. learning from other organizations, including suppliers and competitors) in an emerging market context, in which institutions evolve amid political and policy uncertainty. Finally, this study found that exit and re-entry timing is an important factor for the development of competitive advantage in a host market.
Originality/value
This study is among the few to have investigated the exit and re-entry strategies of MNEs in emerging markets. The relatively short time during which Yamaha Motorcycles had been out of the market had benefited it on its re-entry, as the firm had been able to capitalize on its prior learning and ties to suppliers’ networks.
Details
Keywords
Afshin Yaghoubi and Seyed Taghi Akhavan Niaki
One of the common approaches to improve systems reliability is using standby redundancy. Although many works are available in the literature on the applications of standby…
Abstract
Purpose
One of the common approaches to improve systems reliability is using standby redundancy. Although many works are available in the literature on the applications of standby redundancy, the system components are assumed to be independent of each other. But, in reality, the system components can be dependent on one another, causing the failure of each component to affect the failure rate of the remaining active components. In this paper, a standby two-unit system is considered, assuming a dependency between the switch and its associated active component.
Design/methodology/approach
This paper assumes that the failures between the switch and its associated active component follow the Marshall–Olkin exponential bivariate exponential distribution. Then, the reliability analysis of the system is done using the continuous-time Markov chain method.
Findings
The derived equations application to determine the system steady-state availability, system reliability and sensitivity analysis on the mean time to failure is demonstrated using a numerical illustration.
Originality/value
All previous models assumed independency between the switch and the associated active unit in the standby redundancy approach. In this paper, the switch and its associated component are assumed to be dependent on each other.
Details
Keywords
Chandra Shekhar, Amit Kumar, Shreekant Varshney and Sherif I. Ammar
The internet of things and just-in-time are the embryonic model of innovation for the state-of-the-art design of the service system. This paper aims to develop a fault-tolerant…
Abstract
Purpose
The internet of things and just-in-time are the embryonic model of innovation for the state-of-the-art design of the service system. This paper aims to develop a fault-tolerant machining system with active and standby redundancy. The availability of the fault-tolerant redundant repairable system is a key concern in the successful deployment of the service system.
Design/methodology/approach
In this paper, the authors cogitate a fault-tolerant redundant repairable system of finite working units along with warm standby unit provisioning. Working unit and standby unit are susceptible to random failures, which interrupt the quality-of-service. The system is also prone to common cause failure, which tends its catastrophe. The instantaneous repair of failed unit guarantees the increase in the availability of the unit/system. The time-to-repair by the single service facility for the failed unit follows the arbitrary distribution. For increasing the practicability of the studied model, the authors have also incorporated real-time machining practices such as imperfect coverage of the failure of units, switching failure of standby unit, common cause failure, reboot delay, switch over delay, etc.
Findings
For deriving the explicit expression for steady-state probabilities of the system, the authors use a supplementary variable technique for which the only required input is the Laplace–Stieltjes transform (LST) of the repair time distribution.
Research limitations/implications
For complex and multi-parameters distribution of repair time, derivation of performance measures is not possible. The authors prefer numerical simulation because of its importance in the application for real-time uses.
Practical implications
The stepwise recursive procedure, illustrative examples, and numerical results have been presented for the diverse category of repair time distribution: exponential (M), n-stage Erlang (Ern), deterministic (D), uniform (U(a,b)), n-stage generalized Erlang (GE[n]) and hyperexponential (HE[n]).
Social implications
Concluding remarks and future scopes have also been included. The studied fault-tolerant redundant repairable system is suitable for reliability analysis of a computer system, communication system, manufacturing system, software reliability, service system, etc.
Originality/value
As per the survey in literature, no previous published paper is presented with so wide range of repair time distribution in the machine repair problem. This paper is valuable for system design for reliability analysis of the fault-tolerant redundant repairable.
Details